CYStech Electronics Corp. Spec. No. : C510Q8-A Issued Date : 2003.08.12 Revised Date : Page No. : 1/15 High Performance Current Mode PWM Controllers PL384XAQ8 Description The PL384XAQ8 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 1.0mA, 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 PL3842A and PL3844A have UVLO thresholds of 16V (on) and 10V (off), ideally suited off-line applications. The corresponding thresholds for the PL3843A and PL3845A are 8.5V and 7.9V. The PL3842A and PL3843A can operate to duty cycles approaching 100%. A range of the zero to <50% is obtained by the PL3844A and PL3845A 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 PL3844A and PL3845A) VI 7 UVLO 34V GROUND 8 5V REF S/R 5 INTERNAL BIAS 2.50V VREF GOOD LOGIC 6 4 RT/CT 2 S 2R R COMP CURRENT SENSE PL384XAQ8 1 3 OUTPUT T OSC ERROR AMP. VFB VREF 5V50mA 1V R PWM LATCH CURRENT SENSE COMPARATOR PL3842A CYStek Product Specification CYStech Electronics Corp. Spec. No. : C510Q8-A Issued Date : 2003.08.12 Revised Date : Page No. : 2/15 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) Value 30 Self Limiting ± 1 5 -0.3 to 5.5 10 1.25 -65 to +150 -40 to +150 300 Unit V A µJ 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 VREF VFB VCC ISENSE RT/CT OUTPUT GROUND Pin Functions No Function 1 COMP 2 VFB 3 ISENSE 4 RT/CT 5 6 GROUND OUTPUT 7 8 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 PL384XAQ8 Description Thermal Resistance, junction to ambient Value 150 Unit ℃/W CYStek Product Specification CYStech Electronics Corp. Spec. No. : C510Q8-A Issued Date : 2003.08.12 Revised Date : Page No. : 3/15 Electrical Characteristics (〔note 1〕Unless otherwise stated, these specifications apply for 0≤Tamb≤70℃,Vi=15V(note 5),RT=10k,CT=3.3nF) Parameter Test Conditions Symbol Min. Typ. Max. Unit 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) VREF ∆VREF ∆VREF ∆VREF / ∆T 4.9 5.0 5.1 2 20 3 25 0.2 4.82 5.18 50 5 25 -30 -100 -180 V mV mV mV/℃ V µV mV mA 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 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 = 15kΩ to ground VPIN 2 = 2.7V, RL = 15kΩ to Pin 8 fosc ∆fosc/∆V ∆fosc/∆T Vosc Idischg V2 Ib BW PSRR IO IO 49 48 2257.8 7.6 52 250 0.2 0.5 1.6 8.3 - 55 56 275 1.0 1.0 8.8 8.8 kHz kHz kHz % % V mA mA 2.42 65 0.7 60 2 -0.5 5 - 2.50 2.58 -0.1 -2 90 1 70 12 -1 6.2 0.8 1.1 V µA dB MHz dB mA mA V V 3 3.15 1 1.1 70 -2 -10 150 300 V/V V dB µA ns (note 3 & 4) VPIN 1 = 5V (note 3) 12V ≤ VI ≤ 25V GV V3 SVR Ib 2.85 0.9 - 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 13 12 - Output Section Output Low Level Output High Level UVLO Saturation Rise Time Fall Time PL384XAQ8 VOH VOLS tr tf 0.1 1.6 13.5 13.5 0.1 50 50 0.4 2.2 1.1 150 150 V V V V V ns ns CYStek Product Specification CYStech Electronics Corp. Spec. No. : C510Q8-A Issued Date : 2003.08.12 Revised Date : Page No. : 4/15 Electrical Characteristics (continued) Parameter Test Conditions Symbol Min. Typ. Max. Unit Undervoltage Lockout Section Start Threshold PL3842A/PL3844A 14.5 16 17.5 V PL3843A/PL3845A PL3842A/PL3844A PL3843A/PL3845A 7.8 8.5 7.0 8.4 10 7.6 9.0 11.5 8.2 V PL3842A/PL3843A 94 96 100 % PL3844A/PL3845A 47 48 50 % - - 0 % - 0.17 0.3 mA - 0.17 0.3 mA - 12 17 mA 30 38 - V Min Operating Voltage After Turn-on V PWM Section Maximum Duty Cycle Minimum Duty Cycle Total Standby Current Start-up Current VI=6.5V for PL3843A/45A Ist VI=14V for PL3842A/44A Operating Supply Current VPIN 2 = VPIN 3 = 0V II Zener Voltage II = 25 mA VIZ 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. PL384XAQ8 CYStek Product Specification CYStech Electronics Corp. Spec. No. : C510Q8-A Issued Date : 2003.08.12 Revised Date : Page No. : 5/15 Figure 1: Open Loop Test Circuit VREF RT 4.7k 2N2222 A VREF 100k ERROR AMP. ADJUST COMP VFB 1 0.1uF 8 7 2 VI 1k 0.1uF ISENSE ADJUST 4.7k ISENSE 3 6 4 5 1W 1k OUTPUT OUTPUT 5k RT/CT VI 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 5kΩ potentiometer are used to sample the oscillator waveform and apply an adjustable ramp to pin 3. Figure 3:Output Dead-Time vs Oscillator Frequency Figure 2:Timing Resistor vs Oscillator Frequency 100 100 CT=100pF CT=2nF 500pF 10 Output Dead Time---(%) Timing Resistor---RT(kΩ) 200pF 10nF 5nF 2nF 1nF 10 CT=1nF CT=500p F CT=200pF 10 CT=100pF 1 100 Oscillator Frequency---fosc(kHz) PL384XAQ8 CT=5nF Vi=15V TA=25 Vi=15V,TA=25 ℃ 1 CT=10nF 1000 10 100 1000 Oscillator Frequency---fosc(kHz) CYStek Product Specification CYStech Electronics Corp. Figure 4:Oscillator Discharge Current vs Temperature Figure 5:Maximum Output Duty Cycle vs Timing Resistor 100 Vi=15V VOSC=2V 8.5 Maximum Duty Cycle---Dmax(%) Discharge Current---Idischg(mA) 9 8 7.5 7 90 80 Idischg=7.5mA 70 Idischg=8.8m A 60 Vi=15V CT=3.3nF TA=25℃ 50 40 -50 -25 0 25 50 75 100 125 0.1 1 Ambient Temperature---TA(℃) 10 Timing Resistor---RT(kΩ) Figure 6:Error Amp Open-Loop Gain vs Frequency Figure 7:Error Amp Phase vs Frequency 180 100 Vi=15V,Vo=2 to 4V RL=100l,TA=25℃ 80 Vi=15V,Vo=2 to 4V RL=100k,TA=25 150 60 120 Phase---(deg) Gain---(dB) Spec. No. : C510Q8-A Issued Date : 2003.08.12 Revised Date : Page No. : 6/15 40 20 90 60 0 30 -20 10 100 1000 0 10000 100000 100000 1E+07 0 10 Frequency---f(Hz) Figure 8:Current Sense Input Threshold vs Error Amp Output Voltage 110 Vi=15V 1 Short Circuit Current---ISC(mA) Threshold Voltage---Vth(V) 1000 10000 100000 100000 1E+07 Frequency---f(Hz) 0 Figure 9:Reference Short Circuit Current vs Temperature 1.2 TA=125℃ 0.8 0.6 TA=25℃ 0.4 TA=-40℃ 0.2 0 0 2 4 6 Error Amp Output Voltage---Vo(V) PL384XAQ8 100 8 Vi=15V RL≦0.1Ω 100 90 80 70 60 50 -50 -25 0 25 50 75 100 125 Ambient Temperature---TA(℃) CYStek Product Specification Spec. No. : C510Q8-A Issued Date : 2003.08.12 Revised Date : Page No. : 7/15 CYStech Electronics Corp. Figure 10.Oscillator and Output Waveforms Vi 7 CT 8 5V REG PWM RT 6 OUTPUT OUTPUT CLOCK 4 LARGE RT/SMALL CT OSCILLATOR ID CT CT OUTPUT 5 SMALL RT/LARGE CT GND Figure 11:Error Amp Configuration 2.5V 1mA VFB Zi Zf PL384XAQ8 COMP 2 1 CYStek Product Specification CYStech Electronics Corp. Spec. No. : C510Q8-A Issued Date : 2003.08.12 Revised Date : Page No. : 8/15 Figure 12:Under Voltage Lockout Figure 13:Current Sense Circuit ERROR AMP 2R R Is COMP R 1 1V CURRENT SENSE COMPARATOR 3 CURRENT SENSE Rs C 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. PL384XAQ8 CYStek Product Specification CYStech Electronics Corp. Spec. No. : C510Q8-A Issued Date : 2003.08.12 Revised Date : Page No. : 9/15 Figure 14:Slope Compensation Techniques. VREG Is VREG 8 RT RT RT/CT Is 4 RT/CT CT Rslope R1 8 4 CT ISENSE Rslope 3 R1 5 Rs GND ISENSE 3 5 GND Rs Figure 15:Isolated MOSFET Drive and Current Transformer Sensing Vin VCC 7 ISOLATION BOUNDARY 5.0Vref VGS Waveforms Q1 0 0 6 50% DC S R Ipk Q 25% DC V(pin 1)-1.4 3Rs Ns Np COMP/LATCH R 3 C PL384XAQ8 Rs Ns Np CYStek Product Specification CYStech Electronics Corp. Spec. No. : C510Q8-A Issued Date : 2003.08.12 Revised Date : Page No. : 10/15 Figure 16:Latched Shutdown 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 R RT 4 OSC + CT EXTERNAL SYNC INPUT 0.01μF 2R 47Ω 2 R 1 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. PL384XAQ8 CYStek Product Specification CYStech Electronics Corp. Spec. No. : C510Q8-A Issued Date : 2003.08.12 Revised Date : Page No. : 11/15 Figure 18: Error Amplifier Compensation + From Vo 2.5V 1mA Ri Rd 2R Cf 2 Rf EA R 1 5 Error Amp compensation circuit for stabilizing any current -mode topology except for boost and flyback converters operating with continuous inductor current. + From Vo Rp Cp 2.5V 1mA Ri Rd Cf 2 Rf EA 2R R 1 5 Error Amp compensation circuit for stabilizing current--mode boost and flyback PL384XAQ8 CYStek Product Specification CYStech Electronics Corp. Spec. No. : C510Q8-A Issued Date : 2003.08.12 Revised Date : Page No. : 12/15 Figure 19:External Duty Cycle Clamp and Multi Unit Synchronization PL384XAQ8 CYStek Product Specification CYStech Electronics Corp. Spec. No. : C510Q8-A Issued Date : 2003.08.12 Revised Date : Page No. : 13/15 Figure 20:Soft-Start Circuit 5Vref 8 R BIAS R 4 OSC + 1mA 2 1MΩ S 2R EA Q R R 1V 1 C PL384XAQ8 5 CYStek Product Specification CYStech Electronics Corp. Spec. No. : C510Q8-A Issued Date : 2003.08.12 Revised Date : Page No. : 14/15 Figure 21:Soft-Start and Error Amplifier Output Duty Cycle Clamp. Vcc Vin 7 5Vref 8 R BIAS 7 R 4 Q1 6 OSC + 5 1mA Vclamp 2 S 2R Q R EA R R2 1V Comp/Latch 3 1 5 C BC109 Rs R1 VCLAMP = PL384XAQ8 - R1 R 1+ R 2 where 0< VCLAMP <1V I pk(max) = VCLAMP Rs CYStek Product Specification CYStech Electronics Corp. Spec. No. : C510Q8-A Issued Date : 2003.08.12 Revised Date : Page No. : 15/15 SO-8 Dimension Right side View G Top View A Marking: I C B 384XA H J K E D Front View Part A Part A M L 8-Lead SO-8 Plastic Package CYStek Package Code: Q8 N O F *: Typical DIM Inches Min. Max. 0.1909 0.2007 0.1515 0.1555 0.2283 0.2441 0.0480 0.0519 0.0145 0.0185 0.1472 0.1527 0.0570 0.0649 0.1889 0.2007 A B C D E F G H Millimeters Min. Max. 4.85 5.10 3.85 3.95 5.80 6.20 1.22 1.32 0.37 0.47 3.74 3.88 1.45 1.65 4.80 5.10 DIM I J K L M N O Inches Min. Max. 0.0019 0.0078 0.0118 0.0275 0.0074 0.0098 0.0145 0.0204 0.0118 0.0197 0.0031 0.0051 0.0000 0.0059 Millimeters Min. Max. 0.05 0.20 0.30 0.70 0.19 0.25 0.37 0.52 0.30 0.50 0.08 0.13 0.00 0.15 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. PL384XAQ8 CYStek Product Specification