LM5021 AC-DC Current Mode PWM Controller (jp)

LM5021 LM5021 AC-DC Current Mode PWM Controller Literature Number: JAJSAC6

LM5021 AC-DC PWM LM5021 (PWM) LM5021 (25 A) 1 ( ENERGY STAR CECP ) Hiccup (Hiccup ) 8 LM5021 100ns 1MHz AC-DC PWM 5021 LM Steve Schulte 20050308 24060 ds201442 2005 6 composed for release on CODE S per Campbell. SN composed for Code R. SN composed with edits on text and graphics. SN added engineering disclaimer (on Prelim. documents ONLY). SN composed first pass. SN Copy and renamed from DS200950- LM5020 for shantha - Vee ( 25 A) 0.7A (LM5021-1 80% LM5021-2 50%) (LM5021-1 ) (UVLO) Hiccup : MSOP-8 MDIP-8 LM5021 LM5021 AC-DC PWM 20050509 National Semiconductor Corporation DS201442-02-JP 1

LM5021 TopView MSOP-8 and MDIP-8 1 COMP Hiccup COMP 5k 2 VIN VIN 36V 3 VCC 8.5V VCC LM5021 4 OUT MOSFET MOSFET 0.3A 0.7A 5 GND 6 CS CS 0.5V OUT Low CS OUT High 90ns Low 7 RT / SYNC RT GND 8 SS /Hiccup 22 A Hiccup www.national.com/jpn/ 2

(Note 1) VIN GND 0.3V 30V VIN 5mA CS GND 0.3V 1.25V RT GND 0.3V 5.5V GND 0.3V 7.0V ESD (Note 2) (Note 1) VIN (Note 5) 2kV 65 150 +150 8V 30V 40 125 LM5021 (Note 3) T J 25 V IN 15V R T 44.2K 3 www.national.com/jpn/

LM5021 (Note 3)( ) T J 25 V IN 15V R T 44.2K Note 1: Note 2: Note 3: Note 4: Note 5: 100pF 1.5K Min Max 25 (SQC) (AOQL) VIN 20V www.national.com/jpn/ 4

LM5021 FIGURE 1. 5 www.national.com/jpn/

LM5021 T J 25 VIN Start-Up Current VIN UVLO VIN Current vs OUT Load VIN Voltage Falling vs VCC Voltage OUT Driver Current vs Temperature Hiccup Mode Deadtime vs Softstart Capacitance www.national.com/jpn/ 6

( ) T J 25 Output Switching Frequency vs RT LM5021 Figure 2 AC HV C VIN Rstart C VIN LM5021 VIN 18 A ( ) VIN VIN UVLO 20V VCC VIN UVLO 7.25V (12.5 ) VCC VCC VCC VCC VCC UVLO 7V PWM VCC UVLO 1.2V VCC VCC UVLO Figure 2 ( BIAS WINDING) VIN VCC VIN 11V (VCC VCC ) 30V ( VIN ) VCC UVLO ( 5.8V) VCC Rstart LM5021 Rstart ( 3M ) FIGURE 2 Start-Up Circuit Block Diagram 7 www.national.com/jpn/

LM5021 ( ) C IN V CC C VCC VIN 20V VCC C VIN C VCC VIN VIN' VCC C VCC C VIN VIN x C VIN = DVCC x C VCC (20V - V IN' ) C VIN 8.5V C VCC C VIN 10 F C VCC 1 F VIN 0.85V VIN 19.15V VCC (1 F ) C VIN VCC VIN LM5021 C VIN VCC VCC UVLO VCC LM5021 (Qg) 25nC MOSFET Fsw Qg Fsw 150kHz 3.75mA 2.5mA C VIN 6.25mA C VIN C VIN 8.5V C VIN VIN (19.15V 8.5V) VCC (6.25mA) Tmax Tmax Cin VCC C VIN AC (Figure 2 HV) VIN 20V C VIN PWM / PWM COMP COMP 1.25V 1/3 COMP 1.25V PWM 50 ( ) LM5021-1 CS 1.8k CS 50 LM5021-2 / LM5021 500mV CS 500mV OUT FET CS RC CS PWM 90nS FET LM5021 CS CS (CS GND) FET ( ) RT GND LM5021 50 LM5021-2 2 2 50 LM5021-2 (OUT) 2 1 LM5021-1 (Fsw) RT www.national.com/jpn/ 8

( ) LM5021-1: LM5021-2: LM5021 RT 100pF RT RT 3.8V RT DC 2V RT AC 1.8V 15ns 150ns RT RT LM5021 (RT GND) LM5021 0.3A 0.7A (OUT) LM5021 2 LM5021-1 80 LM5021-2 50 LM5021-2 LM5021-2 PWM (OUT ) 2 LM5021-1 80 LM5021-1 PWM 22 A SS COMP Hiccup Figure3 5 LM5021 Hiccup Css SS 22 A (V SS_OCV 5.2V) COMP SS COMP ( ) COMP 1.25V 2.75V COMP 1.25V COMP 2.75V 0.5V COMP COMP (V OVLD 4.6V) SS Css 10 A I OVCS SS Hiccup (V HIC 4.6V) COMP V OVLD Hiccup OUT Low SS 10 A 0.25 A I DTCS SS (V RST 0.3V) 22 A C SS SS Hiccup MOSFET Hiccup : C SS 0.047 F Toff 808ms Hiccup Hiccup C SS 10 A SS Hiccup Figure5 SS Hiccup LM5021 Hiccup Hiccup 1 : C SS 0.047 F Toverload 2.82ms 9 www.national.com/jpn/

LM5021 ( ) FIGURE 3. Hiccup Mode Control FIGURE 4 Waveform at SS and COMP Pin due to Continuous Overload www.national.com/jpn/ 10

( ) LM5021 FIGURE 5. Waveform at SS and COMP Pin due to Brief Overload MOSFET PWM MOSFET LM5021 COMP Figure 6 PWM 1.25V 3:1 COMP COMP PWM PWM 125mV COMP COMP PWM 130mV (5mV ) 11 www.national.com/jpn/

LM5021 ( ) FIGURE 6. Skip Cycle Control www.national.com/jpn/ 12

LM5021 13 www.national.com/jpn/

LM5021 millimeters 8 Lead MSOP Package NS Package Number MUA08A 8 Lead MDIP Package NS Package Number N08E www.national.com/jpn/ 14

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