MB39A113 Datasheet, PDF (15/51 Pages) Fujitsu Component Limited. – ASSP for Power Supply Applications (Secondary Battery)

MB39A113
(6) Current detection amplifier block (Current Amp1)
The current detection amplifier (Current Amp1) detects voltage drop which occurs between both ends of the
output sense resistor (RS) due to the flow of the charge current, using the +INC1 terminal (pin 13) and −INC1
terminal (pin 12) . Then it outputs the signal amplifier by 20 times to the error amplifier (Error Amp1) at the next
stage.
(7) Current detection amplifier block (Current Amp2)
The current detection amplifier (Current Amp2) detects voltage drop which occurs between both ends of the
output sense resistor (RS) due to the flow of the charge current, using the +INC2 terminal (pin 24) and −INC2
terminal (pin 1) . Then it outputs the signal amplified by 20 times to the error amplifier (Error Amp2) at the next
stage.
(8) PWM comparator block (PWM Comp.)
The PWM comparator circuit is a voltage-to-pulse width modulator that controls the output duty depending on
the output voltage of error amplifier (Error Amp1 to Error Amp3) .
The PWM comparator circuit compares the triangular wave generated by the triangular wave oscillator to the
error amplifier output voltage and turns on the external output transistor during the interval in which the triangular
wave voltage is lower than the error amplifier output voltage.
(9) Output block (OUT)
The output circuit uses a totem-pole configuration capable of driving an external P-channel MOS FET.
The output “L” level sets the output amplitude to 6 V (Typ) using the voltage generated by the bias voltage block
(VH) .
This results in increasing conversion efficiency and suppressing the withstand voltage of the connected external
transistor in a wide range of input voltages.
(10) Power supply control block (CTL)
Setting the CTL terminal (pin 14) low places the IC in the standby mode.
(The supply current is 10 µA at maximum in the standby mode.)
CTL function table
CTL
Power
L
OFF (Standby)
H
ON (Active)
(11) Bias voltage block (VH)
The bias voltage circuit outputs VCC−6 V (Typ) as the minimum potential of the output circuit. In the standby
mode, this circuit outputs the potential equal to VCC.
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