Application Note AN-1150 - International Rectifier

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comparator is decoupled from the averaging circuit thus enabling instantaneous cycle-by-cycle protection for peak current limitation. 5. V CC UVLO In the event that the voltage at the V CC pin should drop below that of the VCC UVLO turn-off threshold, V CC(UVLO) the IC is pushed into the UVLO mode, the gate drive is terminated, and the turn on threshold, V CC, ON must again be exceeded in order to re start the process. In the UVLO mode, the current consumption is less than 75uA. 3. PFC Converter Design Procedure 3.1 PFC Converter Specifications AC Input Voltage Range Input Line Frequency Nominal DC Output Voltage Maximum Output Power Power Factor 85-264VAC 47-63Hz 385V 350W 0.99 @ 115VAC/350W 0.99 @ 230VAC/350W Minimum Output Holdup Time 25ms @ V OUT,MIN =285V Maximum Soft Start Time 60msec Table 1: Design Specifications for PFC Converter www.irf.com AN-1150 6
3.2 Power Circuit Design AC Line Bridge - + AC Neutral L BST D BST V OUT C IN R VFB1 R BOP1 IR1152 IR1145 R R G VFB2 R BOP2 1 C COM GATE 8 OUT 2 M COMP VCC 7 V BST CC 3 ISNS VFB 6 4 BOP OVP/EN 5 R BOP3 R gm C VCC R C C VFB3 BOP P R OVP1 R OVP2 R OVP3 R SF C SF C Z COM R SNS GND Fig.3: IR1152 based PFC Boost Converter Peak Input Current It is necessary to determine the maximum input currents (RMS & peak) from the specifications in Table 1 before proceeding with detailed design of the PFC boost converter. The maximum input current is typically encountered at highest load & lowest input line situation (350W, 85VAC). Assuming a nominal efficiency of 92% at this situation, the maximum input power can be calculated: PO ( MAX ) 350W PIN ( MAX ) = = = 380W η 0.92 From this, the maximum RMS AC line current is then calculated: I I IN ( RMS ) MAX IN ( RMS ) MAX MIN = η MIN ( V P O ( MAX ) IN ( RMS ) MIN ) PF 350W = = 4.5A 0.92(85V )0.998 The selection of the semiconductor components (bridge rectifier, boost switch & boost diode) is based on I IN(RMS)MAX =4.5A. Assuming a pure sinusoidal input, the maximum peak AC line current can then be calculated: I I IN ( PK ) MAX IN ( PK ) MAX = 2( P V IN ( MAX ) IN ( RMS ) MIN 1.414(380W ) = = 6.3A 85V ) www.irf.com AN-1150 7
Page 1 and 2: Application Note AN-1150 Power Fact
Page 3 and 4: • VFB - provides DC bus voltage s
Page 5: one of the comparator misbehaves, t
Page 9 and 10: High Frequency Input Capacitor (C I
Page 11 and 12: V 4.7V ⋅ = 3.1 ( 1− 0.69) ISNS
Page 13 and 14: A standard 1MΩ, 1% tolerance resis
Page 15 and 16: 900mV V BOP 750mV ∆V BOP V BOP,AV
Page 17 and 18: at which the converter is expected
Page 19 and 20: i chg + Voltage loop compensation i
Page 21 and 22: Output voltage sensor Resistor-Divi
Page 23 and 24: Voltage Loop Compensation procedure
Page 25 and 26: 1 1 f P0 = ≅ Cz ⋅Cp 2π ⋅ R 2
Page 27 and 28: • Option 2: At the expense of cur
Page 29 and 30: to IC COM pin. However, in reality,
Page 31 and 32: 4.3 Pin ISNS Current sensing is alw

Application Note AN-1150 - International Rectifier

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