MB39A123 Datasheet, PDF (31/44 Pages) Fujitsu Component Limited. – 6 ch DC/DC Converter IC with Synchronous Rectification

MB39A123
■ OPERATION EXPLANATION WHEN CTL TURNING ON AND OFF
When CTL is turned on, internal reference voltage VR and VREF generate. When VREF exceeds each threshold
voltage (VTH) of UVLO (under voltage lockout protection circuit) , UVLO is released, and the operation of output
drive circuit of each channel becomes possible.
When CTL is off, the CS and CSCP terminals are always set to "L" as soon as output drive circuit of each channel
is fixed to full off even if UVLO is released. When VR and VREF fall and VREF decreases the threshold voltage
(VRST) of UVLO (under voltage lockout protection circuit), output drive circuit becomes the UVLO state.
• CTL block equivalent circuit
SCP
UVLO1
H : at SCP
H : UVLO release
To SCP circuit
H : Possible to
operate SCP
L : CSCP
terminal low
UVLO2
H : UVLO release
ch.1 to ch.4
To output drive circuit
H : Possible to operate
L : Forced stop
CS1 to CS4
To charge/discharge circuit
H : Possible to charge
L : Forced discharge
ch.5, ch.6
To output drive circuit
H : Possible to operate
L : Forced stop
CS5, CS6
To charge/discharge circuit
H : Possible to charge
L : Forced discharge
Error Amp reference
1.0 V/1.23 V
48 VCC
bias
VREF
Power
VR
ON/OFF
1 CTL
CTL
9
VREF
31