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CYStech Electronics Corp. High Performance Current Mode PWM Controllers Spec. No. : C510P8 Issued Date : 2003.04.24 Revised Date : Page No. : 1/15 PL384XBP8 Description The PL384XBP8 family of control ICs provides the necessary features to implement off-line or DC to DC fixed frequency current mode control schemes with a minimal external parts count. Internally implemented circuits include a trimmed oscillator for precise duty cycle control, under voltage lockout featuring start-up current less than 0.5mA, a precision reference trimmed for accuracy at the error amp input, logic to insure latched operation, a PWM comparator which also provides current limit control, and a totem pole output stage designed to source or sink high peak current. The output stage, suitable for driving N-channel MOSFETs, is low in the off-state. Differences between members of this family are the under-voltage lockout thresholds and maximum duty cycle ranges. The PL3842B and PL3844B have UVLO thresholds of 16V (on) and 10V (off), ideally suited off-line applications. The corresponding thresholds for the PL3843B and PL3845B are 8.5V and 7.9V. The PL3842B and PL3843B can operate to duty cycles approaching 100%. A range of the zero to <50% is obtained by the PL3844B and PL3845B by the addition of an internal toggle flip flop which blanks the output off every other clock cycle. Features * Trimmed oscillator for precise frequency control * Oscillator frequency guaranteed at 250 kHz * Current mode operation to 500kHz * Automatic feed forward compensation * Latching PWM for cycle-by-cycle current limiting * Internally trimmed reference with undervoltage lockout * High current totem pole output * Undervoltage lockout with hysteresis * Low start-up and operating current Block Diagram( toggle flip flop used only in PL3844B and PL3845B) VI 7 34V 5 UVLO S/R 5V REF 8 GROUND VREF 5V50mA 2.50V INTERNAL BIAS VREF GOOD LOGIC 6 OUTPUT 4 RT/CT OSC ERROR AMP. VFB 2 T 2R R 1V S R CURRENT SENSE COMPARATOR PWM LATCH COMP 1 CURRENT SENSE 3 PL3842B CYStek Product Specification PL384XBP8 CYStech Electronics Corp. Absolute Maximum Ratings Symbol VI VI IO EO Ptot Tstg TJ TL Parameter Supply Voltage (low impedance source) Supply Voltage (Ii<30mA) Output Current Output Energy (capacitive load) Analog Inputs (pins 2, 3) Error Amplifier Output Sink Current Power Dissipation at Tamb 25 Storage Temperature Range Junction Operating Temperature Lead Temperature (soldering 10s) Spec. No. : C510P8 Issued Date : 2003.04.24 Revised Date : Page No. : 2/15 Value 30 Self Limiting 1 5 -0.3 to 5.5 10 1.25 -65 to +150 -40 to +150 300 Unit V A J V mA W Note : All voltages are with respect to pin 5, all currents are positive into the specified terminal. Pin Connection (top view) COMP VFB ISENSE RT/CT VREF VCC OUTPUT GROUND Pin Functions No Function 1 COMP 2 3 4 5 6 7 8 VFB ISENSE RT/CT GROUND OUTPUT VCC VREF Description This pin is the Error Amplifier output and is made available for loop compensation. This is the inverting input of the Error Amplifier. It is normally connected to the switching power supply output through a resistor divider. A voltage proportional to inductor current is connected to this input. The PWM uses this information to terminate the output switch conduction. The oscillator frequency and maximum output duty cycle are programmed by connecting resistor RT to VREF and capacitor CT to ground. Operation to 500kHz is possible. This pin is the combined control circuitry and power ground. This output directly drives the gate of a power MOSFET. Peak currents up to 1A are sourced and sunk by this pin. This pin is the positive supply of the control IC. This is the reference output. It provides charging current for capacitor CT through resistor RT. Thermal Data Symbol Rth, j-amb Description Thermal Resistance, junction to ambient Value 100 Unit /W PL384XBP8 CYStek Product Specification CYStech Electronics Corp. Spec. No. : C510P8 Issued Date : 2003.04.24 Revised Date : Page No. : 3/15 Electrical Characteristics (note 1Unless otherwise stated, these specifications apply for 0Tamb70,Vi=15V(note 5),RT=10k,CT=3.3nF) Parameter Reference Section Output Voltage Line Regulation Load Regulation Temperature Stability Total Output Variation Output Noise Voltage Long Term Stability Output Short Circuit Oscillator Section Frequency Frequency Change with Volt Frequency Change with Temp Oscillator Voltage Swing Discharge Current (Vosc=2V) Error Amp Section Input Voltage Input Bias Current AVOL Unity Gain Bandwidth Power Supply Rejec. Ratio Output Sink Current Output Source Current VOUT High VOUT Low Current Sense Section Gain Maximum Input Signal Supply Voltage Rejection Input Bias Current Delay to Output Output Section Output Low Level Output High Level UVLO Saturation Rise Time Fall Time PL384XBP8 Test Conditions Tj=25,IO=1mA 12V VI 25V 1mA IO 20mA (Note 2) Line, Load, Temperature 10Hz f 10kHz,Tj=25 (note 2) Tamb=125, 1000 Hrs (note 2) Symbol VREF VREF VREF VREF / T Min. Typ. Max. 4.9 5.0 5.1 2 20 3 25 0.2 4.82 5.18 50 5 25 -30 -100 -180 49 48 2257.8 7.6 2.42 65 0.7 60 2 -0.5 5 2.85 0.9 13 12 52 250 0.2 0.5 1.6 8.3 55 56 275 1.0 1.0 8.8 8.8 Unit V mV mV mV/ V V mV mA kHz kHz kHz % % V mA mA V A dB MHz dB mA mA V V V/V V dB A ns V V V V V ns ns eN ISC Tj=25 TA= 0 to 70 Tj=25(RT=6.2k,CT=1nF) VCC=12V to 25V TA= 0 to 70 Peak to peak TJ=25 TA= 0 to 70 VPIN 1=2.5V VFB=5V 2V Vo 4V TJ = 25 VI = 12V to 25V VPIN 2 = 2.7V, VPIN 1 = 1.1V VPIN 2 = 2.3V, VPIN 1 = 5V VPIN 2 = 2.3V, RL = 15k to ground VPIN 2 = 2.7V, RL = 15k to Pin 8 (note 3 & 4) VPIN 1 = 5V (note 3) 12V VI 25V fosc fosc/V fosc/T Vosc Idischg V2 Ib BW PSRR IO IO 2.50 2.58 -0.1 -2 90 1 70 12 -1 6.2 0.8 1.1 3 3.15 1 1.1 70 -2 -10 150 300 0.1 1.6 13.5 13.5 0.1 50 50 0.4 2.2 1.1 150 150 GV V3 SVR Ib ISINK = 20mA ISINK = 200mA ISOURCE = 20mA ISOURCE = 200mA VCC = 6V, ISINK = 1mA Tj=25, CL=1nF (note 2) Tj=25, CL=1nF (note 2) VOL VOH VOLS tr tf CYStek Product Specification CYStech Electronics Corp. Electrical Characteristics (continued) Parameter Test Conditions Symbol Spec. No. : C510P8 Issued Date : 2003.04.24 Revised Date : Page No. : 4/15 Min. Typ. Max. 14.5 7.8 8.5 7.0 94 47 16 8.4 10 7.6 96 48 0.3 0.3 12 36 17.5 9.0 11.5 8.2 100 50 0 0.5 0.5 17 - Unit V V V Undervoltage Lockout Section Start Threshold PL3842B/PL3844B Min Operating Voltage After Turn-on PWM Section Maximum Duty Cycle Minimum Duty Cycle Total Standby Current Start-up Current Operating Supply Current Zener Voltage VI=6.5V for PL3843B/45B VI=14V for PL3842B/44B VPIN 2 = VPIN 3 = 0V II = 25 mA II VIZ Ist PL3842B/PL3843B PL3844B/PL3845B PL3843B/PL3845B PL3842B/PL3844B PL3843B/PL3845B % % % mA mA mA V 30 Notes: 1. Max. package power dissipation limits must be respected; low duty cycle pulse techniques are used during test maintain Tj as close to Tamb as possible. 2.These parameters, although guaranteed, are not 100% tested in production. 3.Parameter measured at trip point of latch with VPIN 2= 0 . 4.Gain defined as: A= VPIN 1 VPIN 3 , 0 VPIN 3 0.8V 5. Adjust VI above the start threshold before setting at 15V. PL384XBP8 CYStek Product Specification CYStech Electronics Corp. Figure 1: Open Loop Test Circuit Spec. No. : C510P8 Issued Date : 2003.04.24 Revised Date : Page No. : 5/15 VREF RT 4.7k 2N2222 A VREF 100k ERROR AMP. ADJUST COMP VFB 1k ISENSE ADJUST ISENSE 5k RT/CT 0.1uF VI 1 2 8 7 VI 0.1uF 1W 1k OUTPUT 3 4 6 5 4.7k OUTPUT GROUND CT GROUND High peak currents associated with capacitive loads necessitate careful grounding techniques. Timing and bypass capacitors should be connected close to pin 5 in a single point ground. The transistor and 5k potentiometer are used to sample the oscillator waveform and apply an adjustable ramp to pin 3. Figure 2:Timing Resistor vs Oscillator Frequency 100 CT=100pF 200pF 100 Figure 3:Output Dead-Time vs Oscillator Frequency CT=2nF Output Dead Time---(%) CT=1nF 10 CT=500p F CT=200pF CT=10nF CT=5nF Timing Resistor---RT(k) 500pF 10 10nF 5nF 2nF 1nF CT=100pF Vi=15V TA=25 1 1 10 Vi=15V,TA=25 100 Oscillator Frequency---fosc(kHz) 1000 10 100 Oscillator Frequency---fosc(kHz) 1000 PL384XBP8 CYStek Product Specification CYStech Electronics Corp. Figure 4:Oscillator Discharge Current vs Temperature 9 Vi=15V VOSC=2V 100 Maximum Duty Cycle---Dmax(%) 90 80 70 60 50 40 -50 -25 0 25 50 75 100 125 0.1 1 Spec. No. : C510P8 Issued Date : 2003.04.24 Revised Date : Page No. : 6/15 Figure 5:Maximum Output Duty Cycle vs Timing Resistor Discharge Current---Idischg(mA) 8.5 Idischg=7.5mA Idischg=8.8m A Vi=15V CT=3.3nF TA=25 8 7.5 7 Ambient Temperature---TA() Figure 6:Error Amp Open-Loop Gain vs Frequency 100 80 60 Gain---(dB) 40 20 0 Phase---(deg) Vi=15V,Vo=2 to 4V RL=100l,TA=25 10 Timing Resistor---RT(k) Figure 7:Error Amp Phase vs Frequency 180 150 120 90 60 30 Vi=15V,Vo=2 to 4V RL=100k,TA=25 -20 10 100 1000 Frequency---f(Hz) 10000 100000 100000 1E+07 0 0 10 100 1000 10000 100000 100000 1E+07 Frequency---f(Hz) 0 Figure 8:Current Sense Input Threshold vs Error Amp Output Voltage 1.2 Short Circuit Current---ISC(mA) 1 0.8 0.6 Figure 9:Reference Short Circuit Current vs Temperature 110 Vi=15V TA=125 Threshold Voltage---Vth(V) 100 90 80 70 60 50 -50 -25 0 25 50 Vi=15V RL0.1 TA=25 0.4 TA=-40 0.2 0 0 2 4 6 8 Error Amp Output Voltage---Vo(V) 75 100 125 Ambient Temperature---TA() CYStek Product Specification PL384XBP8 CYStech Electronics Corp. Figure 10.Oscillator and Output Waveforms Spec. No. : C510P8 Issued Date : 2003.04.24 Revised Date : Page No. : 7/15 Vi 7 8 PWM RT 4 CLOCK OSCILLATOR CT 5V REG 6 OUTPUT OUTPUT LARGE RT/SMALL CT ID CT CT OUTPUT 5 GND SMALL RT/LARGE CT Figure 11:Error Amp Configuration 2.5V 1mA Zi VFB 2 Zf COMP 1 PL384XBP8 CYStek Product Specification CYStech Electronics Corp. Figure 12:Under Voltage Lockout ICC Spec. No. : C510P8 Issued Date : 2003.04.24 Revised Date : Page No. : 8/15 Vi 7 ON/OFF COMMAND TO REST OF IC <17mA PL3842B PL3843B PL3844B PL3845B VON VOFF 16V 10V 8.4V <0.5mA VCC VOFF VON 7.6V During UVLO, the Output is low Figure 13:Current Sense Circuit ERROR AMP 2R R 1V Is COMP 1 CURRENT SENSE COMPARATOR R Rs C 3 CURRENT SENSE 5 GND Peak Current (is) is determined by the formula IS max 1.0V/Rs A small RC filter may be required to suppress switch transients. PL384XBP8 CYStek Product Specification CYStech Electronics Corp. Figure 14:Slope Compensation Techniques. Spec. No. : C510P8 Issued Date : 2003.04.24 Revised Date : Page No. : 9/15 VREG Is RT RT/CT Rslope R1 CT ISENSE 8 RT 4 Is VREG 8 RT/CT CT 4 3 5 GND Rs Rslope R1 ISENSE 3 5 GND Rs Figure 15:Isolated MOSFET Drive and Current Transformer Sensing Vin VCC 7 ISOLATION BOUNDARY 5.0Vref Q1 0 6 50% DC S R Q V(pin 1)-1.4 3Rs 25% DC Ns Np 0 VGS Waveforms Ipk COMP/LATCH 3 C R Rs Ns Np PL384XBP8 CYStek Product Specification CYStech Electronics Corp. Figure 16:Latched Shutdown Spec. No. : C510P8 Issued Date : 2003.04.24 Revised Date : Page No. : 10/15 4 OSC 8 R BIAS R 1mA 2R 2 EA R 1 5 2N 3905 2N 3903 SCR must be selected for a holding current of less than 0.5mA at TA(min). The simple two transistor circuit can be used in place of the SCR as shown. All resistors are 10K. Figure 17:External Clock Synchronization 8 R BIAS RT R 4 EXTERNAL SYNC INPUT 0.01F CT OSC + 47 2 1 2R R 5 The diode clamp is required if the Sync amplitude is large enough to cause the bottom side of CT to go more than 300mV below ground. PL384XBP8 CYStek Product Specification CYStech Electronics Corp. Figure 18: Error Amplifier Compensation Spec. No. : C510P8 Issued Date : 2003.04.24 Revised Date : Page No. : 11/15 From Vo + 2.5V 1mA 2R Ri Cf 2 Rf 1 EA Rd R 5 Error Amp compensation circuit for stabilizing any current -mode topology except for boost and flyback converters operating with continuous inductor current. From Vo + 2.5V 1mA Ri Rd Cf 2 Rf 1 5 EA 2R R Rp Cp Error Amp compensation circuit for stabilizing current--mode boost and flyback PL384XBP8 CYStek Product Specification CYStech Electronics Corp. Figure 19:External Duty Cycle Clamp and Multi Unit Synchronization Spec. No. : C510P8 Issued Date : 2003.04.24 Revised Date : Page No. : 12/15 VREF RA 8 RB 5K 6 5 5K 2 S R Q 7 3 4 8 R BIAS R 4 + OSC 5K 1 2 2R EA R NE555 1 5 f= 1.44 (RA + 2RB )C Dmax = RB RA + 2RB TO ADDITIONAL PL384XB PL384XBP8 CYStek Product Specification CYStech Electronics Corp. Figure 20:Soft-Start Circuit Spec. No. : C510P8 Issued Date : 2003.04.24 Revised Date : Page No. : 13/15 8 R BIAS R 4 + 5Vref OSC 1mA 2R EA R 1V 5 S Q R 2 1M 1 C PL384XBP8 CYStek Product Specification CYStech Electronics Corp. Figure 21:Soft-Start and Error Amplifier Output Duty Cycle Clamp. Spec. No. : C510P8 Issued Date : 2003.04.24 Revised Date : Page No. : 14/15 Vcc Vin 7 8 R BIAS R 4 + 5Vref 7 OSC 6 Q1 5 1mA Vclamp 2 R2 1 C BC109 R1 5 Rs 2R EA R 1V S Q R Comp/Latch 3 VCLAMP = - R1 R 1 + R2 where 0< VCLAMP <1V I pk(max) = VCLAMP Rs PL384XBP8 CYStek Product Specification CYStech Electronics Corp. DIP-8P Dimension Marking : 8 7 6 5 A 1 2 B 3 4 J F Spec. No. : C510P8 Issued Date : 2003.04.24 Revised Date : Page No. : 15/15 384XB C E DH G M 1 K DIP-8P Plastic Package CYStek Package Code : P8 I L *:Typical DIM A B C D E F G Inches Min. Max. 0.2480 0.2520 0.3630 0.3670 *0.0600 *0.0500 *0.0390 0.1280 0.1320 0.1250 0.1400 Millimeters Min. Max. 6.29 6.40 9.22 9.32 *1.52 *1.27 *0.99 3.25 3.35 3.17 3.55 DIM H I J K L M 1 Inches Min. Max. 0.0150 0.0210 0.0898 0.1098 0.2950 0.3050 *0.1181 0.3370 0.7470 0.0090 0.0150 94 97 Millimeters Min. Max. 0.38 0.53 2.28 2.79 7.49 7.74 *3.00 8.56 8.81 0.229 0.381 94 97 Notes : 1.Controlling dimension : millimeters. 2.Maximum lead thickness includes lead finish thickness, and minimum lead thickness is the minimum thickness of base material. 3.If there is any question with packing specification or packing method, please contact your local CYStek sales office. Material : * Lead : 42 Alloy ; solder plating * Mold Compound : Epoxy resin family, flammability solid burning class:UL94V-0 Important Notice: * All rights are reserved. Reproduction in whole or in part is prohibited without the prior written approval of CYStek. * CYStek reserves the right to make changes to its products without notice. * CYStek semiconductor products are not warranted to be suitable for use in Life-Support Applications, or systems. * CYStek assumes no liability for any consequence of customer product design, infringement of patents, or application assistance. PL384XBP8 CYStek Product Specification |
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