MB3886
Key Features
- Overcurrent protection circuit (requiring no current sense resistor) and overvoltage protection circuit Power-supply voltage range : 5.5 V to 18 V Synchronous rectification system providing high efficiency PSIG pins (open-drain) to output the protection status (Continued) s PACKAGE 30-pin plastic SSOP (FPT-30P-M02) MB3886 (Continued)
- Symmetrical-phase system reducing the input capacitor loss
- Built-in channel control function
- Reference voltage : 3.5 V ± 1%
- Error amplifier threshold voltage : 1.25 V ± 1% (0 °C to 85 °C)
- Oscillator frequency range : 10 kHz to 500 kHz
- Built-in circuit for load-independent soft-start and discharge control
- Totem-pole type output for N-ch MOSFET s PIN ASSIGNMENT (TOP VIEW) PSIG1 : 1 CTL1 : 2 ILIM1 : 3 CT : 4 RT : 5 SGND : 6 CS1 : 7 -INE1 : 8 FB1 : 9 +INC1 : 10 OUT1-1 : 11 VS1 : 12 CB1 : 13 OUT2-1 : 14 PGND : 15 30 : PSIG2 29 : CTL2 28 : ILIM2 27 : VREF 26 : VCC 25 : CSCP 24 : CS2 23 : -INE2 22 : FB2 21 : +INC2 20 : OUT1-2 19 : VS2 18 : CB2 17 : OUT2-2 16 : VB (FPT-30P-M02) 2 MB3886 s PIN DESCRIPTION Pin No. Pin name I/O 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 PSIG1 CTL1 ILIM1 CT RT SGND CS1 -INE1 FB1 +INC1 OUT1-1 VS1 CB1 OUT2-1 PGND VB OUT2-2 CB2 VS2 OUT1-2 +INC2 FB2 -INE2 CS2 CSCP VCC VREF ILIM2 CTL2 PSIG2 O I I Description CH1 protection status output terminal CH1 control terminal “H” level : CH1 ON state “L” level : CH1 OFF state and protection status reset CH1 overcurrent detection resistor connection terminal Triangular waveform oscillation frequency setting capacitor connection terminal Triangular waveform oscillation frequency setting resistor connection terminal Ground terminal CH1 soft-start capacitor connection terminal I O I O CH1 error amp. inverting input terminal CH1 error amp. output terminal CH1 overvoltage comparator noninverting input terminal CH1 totem-pole output terminal (External main-side FET gate drive) CH1 boot capacitor connection terminal Connect a capacitor between the CB1 and VS1 terminals. CH1 totem-pole output terminal (External synchronous-rectification-side FET gate drive) Output circuit bias output terminal CH2 totem-pole output terminal (External synchronous-rectification-side FET gate drive) CH2 boot capacitor connection terminal Connect a capacitor between the CB2 and VS2 terminals. CH2 totem-pole output terminal (External main-side FET gate drive) CH2 error amp. output terminal CH2 error amp. inverting input terminal CH1 external main-side FET source connection terminal O Ground terminal O O CH2 external main-side FET source connection terminal O O I CH2 overvoltage comparator noninverting input terminal CH2 soft-start capacitor connection terminal Timer-latch short-circuit protection capacitor connection terminal Reference voltage, control circuit power supply terminal O I I O Reference voltage output terminal CH2 overcurrent detection resistor connection terminal CH2 control terminal “H” level : CH2 ON state “L” level : CH2 OFF state and protection status reset CH2 protection status output terminal 3 MB3886 s BLOCK DIAGRAM
