MB39A103 Datasheet, PDF (13/33 Pages) List of Unclassifed Manufacturers – 4-Channel DC/DC Converter IC with Support for Low Voltage

MB39A103
2. Channel Control Function
The main or each channel is turned on and off depending on the voltage levels at the CTL terminal (pin 6), CS1
terminal (pin 30), CS2 terminal (pin 1), CS3 terminal (pin 15), and CS4 terminal (pin 16).
Channel On/Off Setting Conditions
CTL
CS1
CS2
CS3
CS4
Power
CH1
CH2
CH3
CH4
L
⎯*
⎯*
⎯*
⎯*
OFF
OFF
OFF
OFF
OFF
H
GND GND GND GND
ON
H
High-Z GND GND GND
ON
H
GND High-Z GND GND
ON
H
GND GND High-Z GND
ON
H
GND GND GND High-Z
ON
H
High-Z High-Z High-Z High-Z
ON
OFF
ON
OFF
OFF
OFF
ON
OFF
OFF
ON
OFF
OFF
ON
OFF
OFF
OFF
ON
OFF
ON
OFF
OFF
OFF
OFF
ON
ON
*: Undefined
3. Protective Functions
(1) Timer-latch short-circuit protection circuit (SCP, SCP Comp.)
The short-circuit detection comparator detects the Error Amp output voltage level of each channel, and if any
channel output voltage of Error Amp reaches the short-circuit detection voltage, the timer circuits are actuated
to start charging the external capacitor CSCP connected to the CSCP terminal (pin 11).
When the capacitor (CSCP) voltage reaches about 0.7 V, the circuit is turned off the output transistor and sets the
dead time to 100 %.
In addition, the short-circuit detection from external input is capable by using −INS terminal (pin 20) on short-
circuit detection comparator (SCP Comp.) .
To release the actuated protection circuit, either the power supply turn off and on again or set the CTL terminal
(pin 6) to the “L” level to lower the VREF terminal (pin 7) voltage to 1.3 V (Min) or less. (See “■SETTING TIME
CONSTANT FOR TIMER-LATCH SHORT-CIRCUIT PROTECTION CIRCUIT”.)
(2) Under voltage lockout protection circuit (UVLO)
The transient state or a momentary decrease in supply voltage, which occurs when the power supply is turned
on, may cause the IC to malfunction, resulting in breakdown or degradation of the system. To prevent such
malfunctions, under voltage lockout protection circuit detects a decrease in internal reference voltage with respect
to the power supply voltage, turns off the output transistor, and sets the dead time to 100% while holding the
CSCP terminal (pin 11) at the “L” level.
The circuit restores the output transistor to normal when the supply voltage reaches the threshold voltage of the
undervoltage lockout protection circuit.
■ PROTECTION CIRCUIT OPERATING FUNCTION TABLE
This table refers to output condition when protection circuit is operating.
Operating circuit
OUT1
OUT2
Short-circuit protection circuit
H
L
Under voltage lockout protection circuit
H
L
OUT3
L
L
OUT4
L
L
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