MB39A132QN-G-ERE1 Datasheet, PDF (23/56 Pages) Fujitsu Component Limited. – ASSP For Power Management Applications (Rechargeable Battery) Synchronous Rectification DC/DC Converter IC for Charging Li-ion Battery

MB39A132
■ SETTING THE CHARGE CURRENT
The error amplifier (Error Amp2) compares the output voltage of charge current control block set by the ADJ2
pin (pin 14) with the output signal from the charge current detection amplifier (Current Amp2), and outputs
a the PWM control signal. The maximum charge current for battery can be set according to the ADJ2 pin
voltage. When a current exceeding the setting current value is going to flow, constant current charge will be
executed at that setting current value, and the charge voltage will drop.
Battery charge current setting voltage: ADJ2
Output voltage in the charge current control block − 0.075
Charge current upper limit Io = _{Current detection amplifier gain (25 V/V Typ) × sense resistor RS(Ω)}
ADJ2 pin input voltage
VREF pin
(ADJ2 pin ≥ 4.6 V)
External Voltage Setting
(ADJ2 pin = GND pin to 4.4 V)
Charge current
control block
output voltage
1.5 V
VADJ2(V)
Charge current
RS = 20 mΩ
RS = 15 mΩ
2.85 A
3.8 A
2 × (ADJ2 pin − 0.075)(A)
2.66 × (ADJ2 pin − 0.075)
(A)
• ADJ2 pin internal circuit
ADJ2 ₁₄
1.5 V
Comparator_D
+
−
4.5 V
Selector
To Error Amp2
• Example of the charge current setting (at RS = 20 mΩ)
Io
8.65 A
4.4 V
2.85 A
0V
4.41 V
ADJ2
External setting when ADJ2 = 0 V to 4.4 V _{4.59 V VREF}
Internal reference voltage setting when ADJ2 = 4.6 V to VREF
DS04–27265–3E
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