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NCV887001D1R2G

NCV887001D1R2G

  • 厂商:

    ONSEMI(安森美)

  • 封装:

    SOIC8

  • 描述:

    SWITCHING CONTROLLER, CURRENT-MO

  • 数据手册
  • 价格&库存
NCV887001D1R2G 数据手册
DATA SHEET www.onsemi.com Automotive Grade Non-Synchronous Boost Controller SOIC−8 D SUFFIX CASE 751 NCV8870 MARKING DIAGRAM The NCV8870 is an adjustable output non−synchronous boost controller which drives an external N-channel MOSFET. The device uses peak current mode control with internal slope compensation. The IC incorporates an internal regulator that supplies charge to the gate driver. Protection features include internally-set soft-start, undervoltage lockout, cycle-by-cycle current limiting, hiccup-mode short-circuit protection and thermal shutdown. Additional features include low quiescent current sleep mode and externally-synchronizable switching frequency. Features • • • • • • • • • • • • • Peak Current Mode Control with Internal Slope Compensation 1.2 V ±2% Reference voltage Fixed Frequency Operation Wide Input Voltage Range of 3.2 V to 40 Vdc, 45 V Load Dump Input Undervoltage Lockout (UVLO) Internal Soft-Start Low Quiescent Current in Sleep Mode Cycle-by-Cycle Current Limit Protection Hiccup-Mode Overcurrent Protection (OCP) Hiccup-Mode Short-Circuit Protection (SCP) Thermal Shutdown (TSD) NCV Prefix for Automotive and Other Applications Requiring Unique Site and Control Change Requirements; AEC−Q100 Qualified and PPAP Capable This is a Pb-Free Device 8 8870xxG ALYW G 1 (Top View) 8870xxG = Specific Device Code xx = 01 A = Assembly Location L = Wafer Lot Y = Year W = Work Week G = Pb−Free Package PIN CONNECTIONS EN/SYNC 1 8 VFB ISNS 2 7 VC GND 3 6 VIN GDRV 4 5 VDRV ORDERING INFORMATION Device Package Shipping† NCV887001D1R2G SOIC−8 (Pb−Free) 2500 / Tape & Reel †For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specification Brochure, BRD8011/D. © Semiconductor Components Industries, LLC, 2017 November, 2021 − Rev. 14 1 Publication Order Number: NCV8870/D NCV8870 6 TEMP VDRV FAULT LOGIC EN/ EN/SYNC OSC 1 SYNC PWM SC VC 5 CLK 7 4 2 CL + RC DRIVE LOGIC CSA 3 Vg VIN D Vo Q GDRV ISNS Co RSNS GND RF1 SCP CC Cg L CDRV VDRV 8 Gm SS VFB RF2 Vref Figure 1. Simplified Block Diagram and Application Schematic PACKAGE PIN DESCRIPTIONS Pin No. Pin Symbol 1 EN/SYNC Function 2 ISNS Current sense input. Connect this pin to the source of the external N-MOSFET, through a current-sense resistor to ground to sense the switching current for regulation and current limiting. 3 GND Ground reference. 4 GDRV Gate driver output. Connect to gate of the external N-MOSFET. A series resistance can be added from GDRV to the gate to tailor EMC performance. 5 VDRV Driving voltage. Internally-regulated supply for driving the external N-MOSFET, sourced from VIN. Bypass with a 1.0 mF ceramic capacitor to ground. 6 VIN Input voltage. If bootstrapping operation is desired, connect a diode from the input supply to VIN, in addition to a diode from the output voltage to VDRV and/or VIN. 7 VC Output of the voltage error amplifier. An external compensator network from VC to GND is used to stabilize the converter. 8 VFB Output voltage feedback. A resistor from the output voltage to VFB with another resistor from VFB to GND creates a voltage divider for regulation and programming of the output voltage. Enable and synchronization input. The falling edge synchronizes the internal oscillator. The part is disabled into sleep mode when this pin is brought low for longer than the enable time-out period. ABSOLUTE MAXIMUM RATINGS (Voltages are with respect to GND, unless otherwise indicated) Rating Value Unit −0.3 to 40 V Peak Transient Voltage (Load Dump on VIN) 45 V Dc Supply Voltage (VDRV, GDRV) 12 V −0.3 to 6 V −0.3 to 3.6 V Dc Voltage (EN/SYNC) −0.3 to 6 V Dc Voltage Stress (VIN − VDRV)* −0.7 to 40 V Operating Junction Temperature −40 to 150 °C Storage Temperature Range −65 to 150 °C Peak Reflow Soldering Temperature: Pb−Free, 60 to 150 seconds at 217°C 265 peak °C Dc Supply Voltage (VIN) Peak Transient Voltage (VFB) Dc Voltage (VC, VFB, ISNS) Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality should not be assumed, damage may occur and reliability may be affected. *An external diode from the input to the VIN pin is required if bootstrapping VDRV and VIN off of the output voltage. www.onsemi.com 2 NCV8870 PACKAGE CAPABILITIES Characteristic ESD Capability (All Pins) Human Body Model Machine Model Value Unit ≥ 2.0 ≥ 200 kV V Moisture Sensitivity Level Package Thermal Resistance Junction-to-Ambient, RqJA (Note 1) 1 − 100 °C/W 1. 1 in2, 1 oz copper area used for heatsinking. Device Variations The NCV8870 features several variants to better fit a multitude of applications. The table below shows the typical values of parameters for the parts that are currently available. TYPICAL VALUES Part No. Dmax fs tss Sa Vcl Isrc Isink VDRV SCE NCV887001 93% 100 kHz 13 ms 33 mV/ms 400 mV 800 mA 600 mA 10.5 V Y DEFINITIONS Symbol Characteristic Dmax Symbol Characteristic Symbol Characteristic Maximum Duty Cycle fs Switching Frequency tss Soft-Start Time Sa Slope Compensating Ramp Vcl Current Limit Trip Voltage Isrc Gate Drive Sourcing Current Isink Gate Drive Sinking Current VDRV Drive Voltage SCE Short Circuit Enable ELECTRICAL CHARACTERISTICS (−40°C < TJ < 150°C, 3.2 V < VIN < 40 V, unless otherwise specified) Min/Max values are guaranteed by test, design or statistical correlation. Characteristic Symbol Conditions Min Typ Max Unit mA GENERAL Quiescent Current, Sleep Mode Iq,sleep VIN = 13.2 V, EN = 0, TJ = 25°C − 2.0 − Quiescent Current, Sleep Mode Iq,sleep VIN = 13.2 V, EN = 0, −40°C < TJ < 125°C − 2.0 6.0 mA Quiescent Current, No switching Iq,off Into VIN pin, EN = 1, No Switching − 1.5 2.5 mA Quiescent Current, Switching, Normal Operation Iq,on Into VIN pin, EN = 1, Switching − 3.0 6.0 mA 200 250 300 ns OSCILLATOR Minimum Pulse Width ton,min Maximum Duty Cycle Dmax NCV887001 91 93 95 % Switching Frequency fs NCV887001 90 100 110 kHz Soft-Start Time tss From start of switching with VFB = 0 until reference voltage = VREF NCV887001 10.5 13 15.5 From EN → 1 until start of switching with VFB = 0 − 720 840 NCV887001 28 33 38 Soft-Start Delay Slope Compensating Ramp tss,dly Sa www.onsemi.com 3 ms ms mV/ms NCV8870 ELECTRICAL CHARACTERISTICS (continued) (−40°C < TJ < 150°C, 3.2 V < VIN < 40 V, unless otherwise specified) Min/Max values are guaranteed by test, design or statistical correlation. Characteristic Symbol Conditions Min Typ Max Unit − 5.0 10 mA 2.0 − 5.0 V ENABLE/SYNCHRONIZATION EN/SYNC Pull-down Current IEN/SYNC EN/SYNC Input High Voltage Vs,ih EN/SYNC Input Low Voltage Vs,il EN/SYNC Time-out Ratio %ten SYNC Minimum Frequency Ratio SYNC Maximum Frequency %fsync,min VEN/SYNC = 5 V VIN > VUVLO 0 − 800 mV From SYNC falling edge, to oscillator control (EN high) or shutdown (EN low), Percent of typical switching period − − 350 % Percent of fs − − 80 % fsync,max 1.1 − − MHz − 50 100 ns 25 − 75 % Input-to-output gain at dc, ISNS ≤ 1 V 0.9 1.0 1.1 V/V 2.5 − − MHz − 30 50 mA 360 400 440 − 80 125 ns 125 150 175 % − 80 125 ns 0.8 1.2 1.63 mS 2.0 − − MW − 0.5 2.0 mA Vref 1.176 1.200 1.224 V VEA Maximum Output Voltage Vc,max 2.5 − − V VEA Minimum Output Voltage Vc,min − − 0.3 V Synchronization Delay ts,dly Synchronization Duty Cycle Dsync From SYNC falling edge to GDRV falling edge under open loop conditions CURRENT SENSE AMPLIFIER Low-frequency Gain Acsa Bandwidth BWcsa Gain of Acsa − 3 dB ISNS Input Bias Current Isns,bias Out of ISNS pin Current Limit Threshold Voltage Vcl Voltage on ISNS pin NCV887001 Current Limit, Response Time tcl CL tripped until GDRV falling edge, VISNS = Vcl(typ) + 60 mV Overcurrent Protection, Threshold Voltage %Vocp Overcurrent Protection, Response Time tocp Percent of Vcl From overcurrent event, Until switching stops, VISNS = VOCP + 40 mV mV VOLTAGE ERROR OPERATIONAL TRANSCONDUCTANCE AMPLIFIER Transconductance gm,vea VEA Output Resistance Ro,vea VFB Input Bias Current Ivfb,bias Reference Voltage VFB – Vref = ±20 mV Current out of VFB pin VEA Sourcing Current Isrc,vea VEA output current, Vc = 2.0 V 80 100 − mA VEA Sinking Current Isnk,vea VEA output current, Vc = 0.7 V 80 100 − mA GATE DRIVER Sourcing Current Isrc VDRV ≥ 6 V, VDRV − VGDRV = 2 V NCV887001 600 800 − Sinking Current Isink VGDRV ≥ 2 V NCV887001 500 600 − VIN − VDRV, IvDRV = 10 mA − 0.2 0.35 V VIN − VDRV = 1 V 10 15 − mA V Driving Voltage Dropout Vdrv,do Driving Voltage Source Current Idrv Backdrive Diode Voltage Drop Vd,bd VDRV − VIN, Id,bd = 5 mA − − 0.7 Driving Voltage VDRV IVDRV = 0.1 − 25 mA NCV887001 10 10.5 11 − 15 − Pull−down resistance Rpd www.onsemi.com 4 mA mA V kW NCV8870 ELECTRICAL CHARACTERISTICS (continued) (−40°C < TJ < 150°C, 3.2 V < VIN < 40 V, unless otherwise specified) Min/Max values are guaranteed by test, design or statistical correlation. Characteristic Symbol Conditions Min Typ Max Unit UVLO Undervoltage Lock-out, Threshold Voltage Vuvlo VIN falling 3.0 3.1 3.2 V Undervoltage Lock-out, Hysteresis Vuvlo,hys VIN rising 50 125 200 mV Startup Blanking Period %tscp,dly From start of soft-start, Percent of tss 100 120 150 % Hiccup-mode Period %thcp,dly From shutdown to start of soft-start, Percent of tss 65 80 95 % VFB as percent of Vref 60 67 75 % tscp From VFB < Vscp to stop switching − 35 100 ns Thermal Shutdown Threshold Tsd TJ rising 160 170 180 °C Thermal Shutdown Hysteresis Tsd,hys TJ falling 10 15 20 °C Thermal Shutdown Delay tsd,dly From TJ > Tsd to stop switching − − 100 ns SHORT CIRCUIT PROTECTION Short Circuit Threshold Voltage Short Circuit Delay %Vscp THERMAL SHUTDOWN Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product performance may not be indicated by the Electrical Characteristics if operated under different conditions. www.onsemi.com 5 NCV8870 TYPICAL PERFORMANCE CHARACTERISTICS 6 TJ = 25°C 6 Iq,sleep, SLEEP CURRENT (mA) Iq,sleep, SLEEP CURRENT (mA) 7 5 4 3 2 1 0 0 10 20 30 VIN, INPUT VOLTAGE (V) VIN = 13.2 V 5 4 3 2 1 0 −50 40 Figure 2. Sleep Current vs. Input Voltage ton,min MINIMUM ON TIME (ns) Iq,on, QUIESCENTCURRENT (mA) 150 100 200 252 VIN = 13.2 V fs = 100 kHz 3.30 3.25 3.20 3.15 3.10 3.05 −50 0 50 100 150 TJ, JUNCTION TEMPERATURE (°C) 250 248 246 244 242 240 238 236 −50 200 0 50 100 150 200 TJ, JUNCTION TEMPERATURE (°C) Figure 4. Quiescent Current vs. Temperature Figure 5. Minimum On Time vs. Temperature 1.010 Vref, REFERENCE VOLTAGE (V) NORMALIZED CURRENT LIMIT (25°C) 1.205 1.005 1.000 0.995 0.990 −40 50 Figure 3. Sleep Current vs. Temperature 3.40 3.35 0 TJ, JUNCTION TEMPERATURE (°C) 10 60 110 TJ, JUNCTION TEMPERATURE (°C) 1.203 1.201 1.199 1.197 1.195 −40 160 10 60 110 TJ, JUNCTION TEMPERATURE (°C) Figure 6. Normalized Current Limit vs. Temperature Figure 7. Reference Voltage vs. Temperature www.onsemi.com 6 160 NCV8870 TYPICAL PERFORMANCE CHARACTERISTICS 8.0 TJ = 25°C 6 Ienable, PULLDOWN CURRENT (mA) Ienable, PULLDOWN CURRENT (mA) 7 5 4 3 2 1 0 0 1 2 3 4 Venable, VOLTAGE (V) 5 6 7.5 7.0 6.5 6.0 5.5 5.0 −40 10 60 110 160 TJ, JUNCTION TEMPERATURE (°C) Figure 8. Enable Pulldown Current vs. Voltage Figure 9. Enable Pulldown Current vs. Temperature THEORY OF OPERATION VIN L Oscillator PWM Comparator − S GDRV Q Gate Drive R + + CO + RL ISNS − CSA Voltage Error VOUT VFB − + VEA NCV8870 Compensation Figure 10. Current Mode Control Schematic Current Mode Control found in voltage mode controllers. The second benefit comes from inherent pulse-by-pulse current limiting by merely clamping the peak switching current. Finally, since current mode commands an output current rather than voltage, the filter offers only a single pole to the feedback loop. This allows for a simpler compensation. The NCV8870 also includes a slope compensation scheme in which a fixed ramp generated by the oscillator is added to the current ramp. A proper slope rate is provided to improve circuit stability without sacrificing the advantages of current mode control. The NCV8870 incorporates a current mode control scheme, in which the PWM ramp signal is derived from the power switch current. This ramp signal is compared to the output of the error amplifier to control the on-time of the power switch. The oscillator is used as a fixed-frequency clock to ensure a constant operational frequency. The resulting control scheme features several advantages over conventional voltage mode control. First, derived directly from the inductor, the ramp signal responds immediately to line voltage changes. This eliminates the delay caused by the output filter and the error amplifier, which is commonly www.onsemi.com 7 NCV8870 Current Limit disabled, it must be disabled for 7 clock cycles before being re-enabled. If the VIN pin voltage falls below VUVLO when EN/SYNC pin is at logic−high, the IC may not power up when VIN returns back above the UVLO. To resume a normal operating state, the EN/SYNC pin must be cycled with a single logic−low to logic−high transition. The NCV8870 features two current limit protections, peak current mode and over current latch off. When the current sense amplifier detects a voltage above the peak current limit between ISNS and GND after the current limit leading edge blanking time, the peak current limit causes the power switch to turn off for the remainder of the cycle. Set the current limit with a resistor from ISNS to GND, with R = VCL / Ilimit. If the voltage across the current sense resistor exceeds the over current threshold voltage the device enters over current hiccup mode. The device will remain off for the hiccup time and then go through the soft−start procedure. UVLO Input Undervoltage Lockout (UVLO) is provided to ensure that unexpected behavior does not occur when VIN is too low to support the internal rails and power the controller. The IC will start up when enabled and VIN surpasses the UVLO threshold plus the UVLO hysteresis and will shut down when VIN drops below the UVLO threshold or the part is disabled. To avoid any lock state under UVLO conditions, the EN/SYNC pin should be in logic−low state. For further details, please refer to EN/SYNC paragraph. Short Circuit Protection If the short circuit enable bit is set (SCE = Y) the device will attempt to protect the power MOSFET from damage. When the output voltage falls below the short circuit trip voltage, after the initial short circuit blanking time, the device enters short circuit latch off. The device will remain off for the hiccup time and then go through the soft-start. Internal Soft-Start To insure moderate inrush current and reduce output overshoot, the NCV8870 features a soft start which charges a capacitor with a fixed current to ramp up the reference voltage. This fixed current is based on the switching frequency, so that if the NCV8870 is synchronized to twice the default switching frequency the soft start will last half as long. EN/SYNC The Enable/Synchronization pin has three modes. When a dc logic high (CMOS/TTL compatible) voltage is applied to this pin the NCV8870 operates at the programmed frequency. When a dc logic low voltage is applied to this pin the NCV8870 enters a low quiescent current sleep mode. When a square wave of at least %fsync,min of the free running switching frequency is applied to this pin, the switcher operates at the same frequency as the square wave. If the signal is slower than this, it will be interpreted as enabling and disabling the part. The falling edge of the square wave corresponds to the start of the switching cycle. If device is VDRV An internal regulator provides the drive voltage for the gate driver. Bypass with a ceramic capacitor to ground to ensure fast turn on times. The capacitor should be between 0.1 mF and 1 mF, depending on switching speed and charge requirements of the external MOSFET. APPLICATION INFORMATION Design Methodology VIN(min): minimum input voltage [V] VIN(max): maximum input voltage [V] VOUT: output voltage [V] IOUT(max): maximum output current [A] ICL: desired typical cycle-by-cycle current limit [A] This section details an overview of the component selection process for the NCV8870 in continuous conduction mode boost. It is intended to assist with the design process but does not remove all engineering design work. Many of the equations make heavy use of the small ripple approximation. This process entails the following steps: 1. Define Operational Parameters 2. Select Current Sense Resistor 3. Select Output Inductor 4. Select Output Capacitors 5. Select Input Capacitors 6. Select Feedback Resistors 7. Select Compensator Components 8. Select MOSFET(s) 9. Select Diode 10. Determine Feedback Loop Compensation Network From this the ideal minimum and maximum duty cycles can be calculated as follows: D min + 1 * D max + 1 * V IN(max) V OUT V IN(min) V OUT Both duty cycles will actually be higher due to power loss in the conversion. The exact duty cycles will depend on conduction and switching losses. If the maximum input voltage is higher than the output voltage, the minimum duty cycle will be negative. This is because a boost converter cannot have an output lower than the input. In situations where the input is higher than the output, the output will 1. Define Operational Parameters Before beginning the design, define the operating parameters of the application. These include: www.onsemi.com 8 NCV8870 follow the input, minus the diode drop of the output diode and the converter will not attempt to switch. If the calculated Dmax is higher the Dmax of the NCV8870, the conversion will not be possible. It is important for a boost converter to have a restricted Dmax, because while the ideal conversion ration of a boost converter goes up to infinity as D approaches 1, a real converter’s conversion ratio starts to decrease as losses overtake the increased power transfer. If the converter is in this range it will not be able to regulate properly. If the following equation is not satisfied, the device will skip pulses at high VIN: I L,peak + I L,avg ) 4. Select Output Capacitors The output capacitors smooth the output voltage and reduce the overshoot and undershoot associated with line transients. The steady state output ripple associated with the output capacitors can be calculated as follows: V OUT(ripple) + DI OUT(max) fC OUT ) ǒ I OUT(max) 1*D ) V IN(min)D 2fL Ǔ R ESR The capacitors need to survive an RMS ripple current as follows: Where: fs: switching frequency [Hz] ton(min): minimum on time [s] I Cout(RMS) + I OUT 2. Select Current Sense Resistor Current sensing for peak current mode control and current limit relies on the MOSFET current signal, which is measured with a ground referenced amplifier. The easiest method of generating this signal is to use a current sense resistor from the source of the MOSFET to device ground. The sense resistor should be selected as follows: Ǹ D WC D ) WC 12 DȀ WC ǒ DȀ WC L R OUT T SW Ǔ 2 The use of parallel ceramic bypass capacitors is strongly encouraged to help with the transient response. 5. Select Input Capacitors The input capacitor reduces voltage ripple on the input to the module associated with the ac component of the input current. V R S + CL I CL Where: RS: sense resistor [W] VCL: current limit threshold voltage [V] ICL: desire current limit [A] I Cin(RMS) + V IN(min) 2 D WC Lf sV OUT2 Ǹ3 6. Select Feedback Resistors 3. Select Output Inductor The feedback resistors form a resistor divider from the output of the converter to ground, with a tap to the feedback pin. During regulation, the divided voltage will equal Vref. The lower feedback resistor can be chosen, and the upper feedback resistor value is calculated as follows: The output inductor controls the current ripple that occurs over a switching period. A high current ripple will result in excessive power loss and ripple current requirements. A low current ripple will result in a poor control signal and a slow current slew rate in case of load steps. A good starting point for peak to peak ripple is around 20−40% of the inductor current at the maximum load at the worst case VIN, but operation should be verified empirically. The worst case VIN is half of VOUT, or whatever VIN is closest to half of VOUT. After choosing a peak current ripple value, calculate the inductor value as follows: R upper + R lower ǒV out * V refǓ V ref The total feedback resistance (Rupper + Rlower) should be in the range of 1 kW – 100 kW. 7. Select Compensator Components Current Mode control method employed by the NCV8870 allows the use of a simple, Type II compensation to optimize the dynamic response according to system requirements. V IN(WC) D WC DI L,max f s Where: VIN(WC): VIN value as close as possible to half of VOUT [V] DWC: duty cycle at VIN(WC) DIL,max: maximum peak to peak ripple [A] The maximum average inductor current can be calculated as follows: I L,AVG + 2 Where: IL,peak: Peak inductor current value [A] D min w t on(min) fs L+ DI L,max 8. Select MOSFET(s) In order to ensure the gate drive voltage does not drop out the MOSFET(s) chosen must not violate the following inequality: Q g(total) v V OUTI OUT(max) V IN(min)h The Peak Inductor current can be calculated as follows: www.onsemi.com 9 I drv fs NCV8870 compensation network, stable regulation response is achieved for input line and load transients. Compensator design involves the placement of poles and zeros in the closed loop transfer function. Losses from the boost inductor, MOSFET, current sensing and boost diode losses also influence the gain and compensation expressions. The OTA has an ESD protection structure (RESD ≈ 502 W, data not provided in the datasheet) located on the die between the OTA output and the IC package compensation pin (VC). The information from the OTA PWM feedback control signal (VCTRL) may differ from the IC-VC signal if R2 is of similar order of magnitude as RESD . The compensation and gain expressions which follow take influence from the OTA output impedance elements into account. Type-I compensation is not possible due to the presence of RESD . The Figures 11 and 12 compensation networks correspond to a Type-II network in series with RESD . The resulting control-output transfer function is an accurate mathematical model of the IC in a boost converter topology. The model does have limitations and a more accurate SPICE model should be considered for a more detailed analysis: • The attenuating effect of large value ceramic capacitors in parallel with output electrolytic capacitor ESR is not considered in the equations. • The CCM Boost control-output transfer function includes operating efficiency as a correction factor to improve modeling accuracy under low input voltage and high output current operating conditions where operating losses becomes significant. Where: Qg(total): Total Gate Charge of MOSFET(s) [C] Idrv: Drive voltage current [A] fs: Switching Frequency [Hz] The maximum RMS Current can be calculated as follows: I Q(max) + I out ǸD DȀ The maximum voltage across the MOSFET will be the maximum output voltage, which is the higher of the maximum input voltage and the regulated output voltaged: V Q(max) + V OUT(max) 9. Select Diode The output diode rectifies the output current. The average current through diode will be equal to the output current: I D(avg) + I OUT(max) Additionally, the diode must block voltage equal to the higher of the output voltage and the maximum input voltage: V D(max) + V OUT(max) The maximum power dissipation in the diode can be calculated as follows: P D + V f (max) I OUT(max) Where: Pd: Power dissipation in the diode [W] Vf(max): Maximum forward voltage of the diode [V] 10. Determine Feedback Loop Compensation Network The purpose of a compensation network is to stabilize the dynamic response of the converter. By optimizing the L rL VIN Vd VOUT rCf COUT Rds(on) VC GDRV R2 RESD C2 C1 ISNS VCTRL OTA Ri R0 VFB GND R1 Rlow Figure 11. NCV8870 Boost Converter OTA and Compensation www.onsemi.com 10 ROUT NCV8870 Vd VIN VOUT 1:N rCf Lp COUT Rds(on) VC ROUT GDRV R2 RESD C2 C1 ISNS VCTRL OTA R0 Ri VREF VFB GND R1 Rlow Figure 12. NCV8870 Flyback Converter OTA and Compensation Necessary equations for describing the modulator gain (Vctrl-to-Vout gain) Hctrl_output (f) are described next. Boost continuous conduction mode (CCM) and discontinuous conduction mode (DCM) transfer function expressions are summarized in Table 1. Flyback CCM and DCM transfer function expressions are summarized in Table 2. The following equations may be used to select compensation components R2 , C1 , C2 for Figures 11 & 12 power supply. Required input design parameters for analysis are: Vd = Output diode Vf (V) VIN = Power supply input voltage (V) N = Ns /Np (Flyback transformer turns ratio) Ri = Current sense resistor (W) RDS(on) = MOSFET RDS(on) (W) (Rsw_eq = RDS(on) + Ri for the boost continuous conduction mode (CCM) expressions) COUT = Bulk output capacitor value (F) rCF = Bulk output capacitor ESR (W) ROUT = Equivalent resistance of output load (W) Pout = Output Power (W) L = Boost inductor value or flyback transformer primary side inductance (H) rL = Boost inductor ESR (W) Ts = 1/fs , where fs = clock frequency (Hz) R1 and Rlow = Feedback resistor divider values used to set the output voltage (W) VOUT = Device specific output voltage (defined by R1 and Rlow values) (V) R0 = OTA output resistance = 3 MW Sa = IC slope compensation (e.g. 33 mV/ms for NCV887001) gm = OTA transconductance = 1.2 mS D = Controller duty ratio D’ = 1 − D www.onsemi.com 11 NCV8870 Table 1. BOOST CCM AND DCM TRANSFER FUNCTION EXPRESSIONS CCM Duty Ratio (D) ȡ ȧ ȧ ȧ Ȣ -V OUT DCM ƪ 2R OUTV dV IN* R sw_eq)R OUT Ǹ ǒ ǒ V IN V OUT *2 V OUT 2 Ǔ ȣ ȧ ȧ ȧ Ȥ R OUTV IN 2)2R sw_eqV INV OUT*4V dR sw_eqV IN R OUT )R sw_eq 2V OUT 2 -4R sw_eqV OUT 2*4r LV dV IN*4r LV OUT 2 ǒ 2R OUT V OUT 2 ) V dV IN VOUT/VIN DC Conversion Ratio (M) Ǔƫ Ǹ2tLM(M * 1) L Where: t L + R OUTT s Ǔ ȱ ȳ (1 * D)V ȧ 1 ȧ 1 ƪ ƫ 1* ȧ ȧ V 1*D 1 ȧ1 ) ȧ r )DR (1*D) ǒ Ǔ R Ȳ ȴ d out 2 1 2 ǒ Ǹ 1) 1) 2D 2 tL Ǔ sw_eq L OUT V IN * I Laveǒr L ) R sw_eqǓ Inductor On-slope (Sn ), V/s Ri L Where average inductor current: Compensation Ramp (mc ) Right-Half-Plane Zero (wz2 ) (1 * D) L Low Frequency Modulator Pole (wp1 ) 2 I Lave + P out 1 r CFC OUT r CFC OUT ǒ r CFR OUT R OUT * r CF ) R OUT Ǔ * rL R OUT L M 2L 1 R CFC OUT 2F SW p Sampling Double Pole (wn ) 1 1 ǒ R OUTT s 1 Sa 2M ) ) 2 Sn LM 2 p1 Ǔ D S nm cT s hR OUT 2V OUT Ri D Ǔǒ 2 1 z1 z2 1)j 2pf 2 2pf ) ǒj w Ǔ n w nQ p www.onsemi.com 12 @ M*1 2M * 1 ǒ1 ) j w2pfǓǒ1 * j w2pfǓ ǒ1 ) j w2pfǓǒ1 * j w2pfǓ 2pf 1 )jw 1 1*M − p(m c(1 * D) * 0.5) Hd M*1 − Ts Fm 2M * 1 @ ǒ Ǔ − ǒ Sn 1 High Frequency Modulator Pole (wp2 ) F mH d Sa 1) Sn Ts 2 ) mc R OUT LM 3 Sampling Quality Coefficient (Qp ) Ri V INh C OUT Control-Output Transfer Function (Hctrl_output (f)) L Sa 1) Cout ESR Zero (wz1 ) V IN Ǔ F mH d z1 ǒ 2pf 1 )jw p1 Ǔǒ z2 2pf 1 ) jw p2 Ǔ NCV8870 Table 2. FLYBACK CCM AND DCM TRANSFER FUNCTION EXPRESSIONS CCM DCM Duty ratio (D) V OUT V OUT V OUT ) NV IN VOUT/VIN DC Conversion Ratio (M) Compensation Ramp (mc ) 1*D V IN V IN Cout ESR Zero (wz1 ) Right-Half-Plane Zero (wz2 ) Ri Lp Sa 1) 1 r CFC OUT (1 * D) R OUT R OUT DL pN 2 N 2L ǒ @ p 1 M(M ) 1) Ǔ 2 R OUTC OUT ǒ Ǔ wp2 − 1 ǒ 2F SW 2 1 1)M S nm cT s R OUT V IN R iN ǒ1 ) j w2pfǓǒ1 * j w2pfǓ 2pf 1 ) jw p1 F mH d Ǔ Once the desired cross-over frequency (fc ) gain adjustment and necessary phase boost are determined from the Hctrl_output (f) gain and phase plots, the Table 3 equations may be used. It should be noted that minor compensation Ǹ 1 2t L ǒ1 ) j w2pfǓǒ1 * j w2pfǓ z2 z1 ǒ 1 D 1 Ǔ Sa DȀ 2 t L  1 ) 2 S n ) 2M ) 1 F mH d Sn 1 Sa DȀ 3 t L  1 ) 2 S n ) 1 ) D Control-output Transfer Function (Hctrl_output (f)) Ri r CFC OUT 2 Hd T sR OUT Sa 1) Sn R OUTC OUT Fm N 2L p N@D Ǹ2 @ tL Lp Modulator Pole (wp1 ) Where: t L + N@D Inductor On-slope (Sn ), V/s Ǹ2t L NV IN z1 ǒ 2pf 1 )jw p1 Ǔǒ z2 2pf 1 ) jw p2 Ǔ component value adjustments may become necessary when R2 ≤ ~10·Resd as a result of approximations for determining components R2 , C1 , C2 . www.onsemi.com 13 NCV8870 Table 3. OTA COMPENSATION TRANSFER FUNCTION AND COMPENSATION VALUES Desired OTA Gain at Cross-over Frequency fc (G) desired_G fc_gain_db 20 10 ǒq Desired Phase Boost at Cross-over Frequency fc (boost) Ǔ 180° * 90° Ǔ p ǒ ( ) margin * arg H ctrl_output fc p 180° w p1e Select OTA Compensation Zero to Coincide with Modulator Pole at fp1 (fz ) 2p Resulting OTA High Frequency Pole Placement (fp ) f zf c ) f c 2 tan(boost) f c * f z tan(boost) Compensation Resistor R2 V OUT   f p * f z 1.2g m f pG Ǹ 1) Ǹ 1) Compensation Capacitor C1 ǒǓ 2 fc fp ǒǓ fz fp 1 2pf zR 2 Compensation Capacitor C2 1 2pf pG OTA DC Gain (G0_OTA ) @ R lowg m R low ) R 1 R low R low ) R 1 ȳ R R C 1* 1*4 ȧ ȧ 2 R R C ǒR ) R Ǔ C ȴ Ȳ ǒ Ǔ ȳ R R C 1 R )R ȱ  1) 1*4 ȧ ȧ 2 R R C ǒR ) R Ǔ C ȴ Ȳ ǒ Ǔȱ ȳ R ǒR ) R ǓC 1 R )R )R  1 * 1 * 4  ȧ ȧ 2 R ǒR ) R ǓC ǒR ) R ) R Ǔ C ȴ Ȳ ǒ Ǔȱ ȳ R ǒR ) R ǓC 1 R )R )R  1) 1*4 ȧ ȧ 2 R ǒR ) R ǓC ǒR ) R ) R Ǔ C ȴ Ȳ ǒ1 ) j w Ǔ ǒ1 ) j w2pf Ǔ Low Frequency Zero (wz1e ) 1  ǒR2 ) ResdǓȱ @ gm @ R0 2 esd 2 High Frequency Zero (wz2e ) 2 0 2 High Frequency Pole (wp2e ) 2 0 0 2 OTA Transfer Function (GOTA (f)) 2 0 2 esd esd 2 esd 2 2 2 1 esd Ǹ Ǹ esd esd 2 esd 2 2 2 1 esd Ǹ esd 2 esd 2 Low Frequency Pole (wp1e ) Ǹ 2 2 0 0 2 2 0 esd 2 2 1 esd 0 esd 2 esd 2 2 1 2pf z2e z1e -G 0_OTA The open-loop-response in closed-loop form to verify the gain/phase margins may be obtained from the following expression. ǒ  2pf 1 ) jw p1e Ǔǒ 2pf 1 )jw p2e Ǔ device. Simply connect the voltage you would like to boost to the inductor and connect the stable voltage to the VIN pin of the device. In boost configuration, the output of the converter can be used to power the device. In some cases it may be desirable to connect 2 sources to VIN pin, which can be accomplished simply by connecting each of the sources through a diode to the VIN pin. T(f) + G OTA(f) H ctrl_output(f) Low Voltage Operation If the input voltage drops below the UVLO or MOSFET threshold voltage, another voltage may be used to power the www.onsemi.com 14 MECHANICAL CASE OUTLINE PACKAGE DIMENSIONS SOIC−8 NB CASE 751−07 ISSUE AK 8 1 SCALE 1:1 −X− DATE 16 FEB 2011 NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: MILLIMETER. 3. DIMENSION A AND B DO NOT INCLUDE MOLD PROTRUSION. 4. MAXIMUM MOLD PROTRUSION 0.15 (0.006) PER SIDE. 5. DIMENSION D DOES NOT INCLUDE DAMBAR PROTRUSION. ALLOWABLE DAMBAR PROTRUSION SHALL BE 0.127 (0.005) TOTAL IN EXCESS OF THE D DIMENSION AT MAXIMUM MATERIAL CONDITION. 6. 751−01 THRU 751−06 ARE OBSOLETE. NEW STANDARD IS 751−07. A 8 5 S B 0.25 (0.010) M Y M 1 4 −Y− K G C N X 45 _ SEATING PLANE −Z− 0.10 (0.004) H M D 0.25 (0.010) M Z Y S X J S 8 8 1 1 IC 4.0 0.155 XXXXX A L Y W G IC (Pb−Free) = Specific Device Code = Assembly Location = Wafer Lot = Year = Work Week = Pb−Free Package XXXXXX AYWW 1 1 Discrete XXXXXX AYWW G Discrete (Pb−Free) XXXXXX = Specific Device Code A = Assembly Location Y = Year WW = Work Week G = Pb−Free Package *This information is generic. Please refer to device data sheet for actual part marking. Pb−Free indicator, “G” or microdot “G”, may or may not be present. Some products may not follow the Generic Marking. 1.270 0.050 SCALE 6:1 INCHES MIN MAX 0.189 0.197 0.150 0.157 0.053 0.069 0.013 0.020 0.050 BSC 0.004 0.010 0.007 0.010 0.016 0.050 0 _ 8 _ 0.010 0.020 0.228 0.244 8 8 XXXXX ALYWX G XXXXX ALYWX 1.52 0.060 0.6 0.024 MILLIMETERS MIN MAX 4.80 5.00 3.80 4.00 1.35 1.75 0.33 0.51 1.27 BSC 0.10 0.25 0.19 0.25 0.40 1.27 0_ 8_ 0.25 0.50 5.80 6.20 GENERIC MARKING DIAGRAM* SOLDERING FOOTPRINT* 7.0 0.275 DIM A B C D G H J K M N S mm Ǔ ǒinches *For additional information on our Pb−Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D. STYLES ON PAGE 2 DOCUMENT NUMBER: DESCRIPTION: 98ASB42564B SOIC−8 NB Electronic versions are uncontrolled except when accessed directly from the Document Repository. Printed versions are uncontrolled except when stamped “CONTROLLED COPY” in red. PAGE 1 OF 2 onsemi and are trademarks of Semiconductor Components Industries, LLC dba onsemi or its subsidiaries in the United States and/or other countries. onsemi reserves the right to make changes without further notice to any products herein. onsemi makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does onsemi assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. onsemi does not convey any license under its patent rights nor the rights of others. © Semiconductor Components Industries, LLC, 2019 www.onsemi.com SOIC−8 NB CASE 751−07 ISSUE AK DATE 16 FEB 2011 STYLE 1: PIN 1. EMITTER 2. COLLECTOR 3. COLLECTOR 4. EMITTER 5. EMITTER 6. BASE 7. BASE 8. EMITTER STYLE 2: PIN 1. COLLECTOR, DIE, #1 2. COLLECTOR, #1 3. COLLECTOR, #2 4. COLLECTOR, #2 5. BASE, #2 6. EMITTER, #2 7. BASE, #1 8. EMITTER, #1 STYLE 3: PIN 1. DRAIN, DIE #1 2. DRAIN, #1 3. DRAIN, #2 4. DRAIN, #2 5. GATE, #2 6. SOURCE, #2 7. GATE, #1 8. SOURCE, #1 STYLE 4: PIN 1. ANODE 2. ANODE 3. ANODE 4. ANODE 5. ANODE 6. ANODE 7. ANODE 8. COMMON CATHODE STYLE 5: PIN 1. DRAIN 2. DRAIN 3. DRAIN 4. DRAIN 5. GATE 6. GATE 7. SOURCE 8. SOURCE STYLE 6: PIN 1. SOURCE 2. DRAIN 3. DRAIN 4. SOURCE 5. SOURCE 6. GATE 7. GATE 8. SOURCE STYLE 7: PIN 1. INPUT 2. EXTERNAL BYPASS 3. THIRD STAGE SOURCE 4. GROUND 5. DRAIN 6. GATE 3 7. SECOND STAGE Vd 8. FIRST STAGE Vd STYLE 8: PIN 1. COLLECTOR, DIE #1 2. BASE, #1 3. BASE, #2 4. COLLECTOR, #2 5. COLLECTOR, #2 6. EMITTER, #2 7. EMITTER, #1 8. COLLECTOR, #1 STYLE 9: PIN 1. EMITTER, COMMON 2. COLLECTOR, DIE #1 3. COLLECTOR, DIE #2 4. EMITTER, COMMON 5. EMITTER, COMMON 6. BASE, DIE #2 7. BASE, DIE #1 8. EMITTER, COMMON STYLE 10: PIN 1. GROUND 2. BIAS 1 3. OUTPUT 4. GROUND 5. GROUND 6. BIAS 2 7. INPUT 8. GROUND STYLE 11: PIN 1. SOURCE 1 2. GATE 1 3. SOURCE 2 4. GATE 2 5. DRAIN 2 6. DRAIN 2 7. DRAIN 1 8. DRAIN 1 STYLE 12: PIN 1. SOURCE 2. SOURCE 3. SOURCE 4. GATE 5. DRAIN 6. DRAIN 7. DRAIN 8. DRAIN STYLE 13: PIN 1. N.C. 2. SOURCE 3. SOURCE 4. GATE 5. DRAIN 6. DRAIN 7. DRAIN 8. DRAIN STYLE 14: PIN 1. N−SOURCE 2. N−GATE 3. P−SOURCE 4. P−GATE 5. P−DRAIN 6. P−DRAIN 7. N−DRAIN 8. N−DRAIN STYLE 15: PIN 1. ANODE 1 2. ANODE 1 3. ANODE 1 4. ANODE 1 5. CATHODE, COMMON 6. CATHODE, COMMON 7. CATHODE, COMMON 8. CATHODE, COMMON STYLE 16: PIN 1. EMITTER, DIE #1 2. BASE, DIE #1 3. EMITTER, DIE #2 4. BASE, DIE #2 5. COLLECTOR, DIE #2 6. COLLECTOR, DIE #2 7. COLLECTOR, DIE #1 8. COLLECTOR, DIE #1 STYLE 17: PIN 1. VCC 2. V2OUT 3. V1OUT 4. TXE 5. RXE 6. VEE 7. GND 8. ACC STYLE 18: PIN 1. ANODE 2. ANODE 3. SOURCE 4. GATE 5. DRAIN 6. DRAIN 7. CATHODE 8. CATHODE STYLE 19: PIN 1. SOURCE 1 2. GATE 1 3. SOURCE 2 4. GATE 2 5. DRAIN 2 6. MIRROR 2 7. DRAIN 1 8. MIRROR 1 STYLE 20: PIN 1. SOURCE (N) 2. GATE (N) 3. SOURCE (P) 4. GATE (P) 5. DRAIN 6. DRAIN 7. DRAIN 8. DRAIN STYLE 21: PIN 1. CATHODE 1 2. CATHODE 2 3. CATHODE 3 4. CATHODE 4 5. CATHODE 5 6. COMMON ANODE 7. COMMON ANODE 8. CATHODE 6 STYLE 22: PIN 1. I/O LINE 1 2. COMMON CATHODE/VCC 3. COMMON CATHODE/VCC 4. I/O LINE 3 5. COMMON ANODE/GND 6. I/O LINE 4 7. I/O LINE 5 8. COMMON ANODE/GND STYLE 23: PIN 1. LINE 1 IN 2. COMMON ANODE/GND 3. COMMON ANODE/GND 4. LINE 2 IN 5. LINE 2 OUT 6. COMMON ANODE/GND 7. COMMON ANODE/GND 8. LINE 1 OUT STYLE 24: PIN 1. BASE 2. EMITTER 3. COLLECTOR/ANODE 4. COLLECTOR/ANODE 5. CATHODE 6. CATHODE 7. COLLECTOR/ANODE 8. COLLECTOR/ANODE STYLE 25: PIN 1. VIN 2. N/C 3. REXT 4. GND 5. IOUT 6. IOUT 7. IOUT 8. IOUT STYLE 26: PIN 1. GND 2. dv/dt 3. ENABLE 4. ILIMIT 5. SOURCE 6. SOURCE 7. SOURCE 8. VCC STYLE 29: PIN 1. BASE, DIE #1 2. EMITTER, #1 3. BASE, #2 4. EMITTER, #2 5. COLLECTOR, #2 6. COLLECTOR, #2 7. COLLECTOR, #1 8. COLLECTOR, #1 STYLE 30: PIN 1. DRAIN 1 2. DRAIN 1 3. GATE 2 4. SOURCE 2 5. SOURCE 1/DRAIN 2 6. SOURCE 1/DRAIN 2 7. SOURCE 1/DRAIN 2 8. GATE 1 DOCUMENT NUMBER: DESCRIPTION: 98ASB42564B SOIC−8 NB STYLE 27: PIN 1. ILIMIT 2. OVLO 3. UVLO 4. INPUT+ 5. SOURCE 6. SOURCE 7. SOURCE 8. DRAIN STYLE 28: PIN 1. SW_TO_GND 2. DASIC_OFF 3. DASIC_SW_DET 4. GND 5. V_MON 6. VBULK 7. VBULK 8. VIN Electronic versions are uncontrolled except when accessed directly from the Document Repository. Printed versions are uncontrolled except when stamped “CONTROLLED COPY” in red. PAGE 2 OF 2 onsemi and are trademarks of Semiconductor Components Industries, LLC dba onsemi or its subsidiaries in the United States and/or other countries. onsemi reserves the right to make changes without further notice to any products herein. onsemi makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does onsemi assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. onsemi does not convey any license under its patent rights nor the rights of others. © Semiconductor Components Industries, LLC, 2019 www.onsemi.com onsemi, , and other names, marks, and brands are registered and/or common law trademarks of Semiconductor Components Industries, LLC dba “onsemi” or its affiliates and/or subsidiaries in the United States and/or other countries. onsemi owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. 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