M61041FP

Rev.1.0, Sep.19.2003, page 13 of 28

Description of Circuit Blocks

(1) Battery Voltage Detect Circuit

As shown in figure 6, the battery voltage detect circuit block of the M61041FP consists of switches, a buffer

amplifier, a reference voltage circuit, and a logic circuit.

When the voltage to be detected is selected, based on serial data from the microprocessor, the appropriate switch

connections are determined by the logic circuit. The voltages Vbat1, Vbat2, Vbat3, and Vbat4 from the batteries

connected to the M61041FP, multiplied by Gamp1 (1.0), are output from the Analog_out pin. It is also possible to

output an offset voltage.

In the power-save mode all the switches are turned off, so the current consumption of this circuit block is zero.

Note : The settling time of this circuit block after voltage changes is about 50 µs.

GND

VIN_4

VIN_3

VIN_1

VIN_2

Vbat4

Vbat3

Vbat2

Vbat1

S01

S02

S42

S41

S32

S31

Switch control

From serial/parallel

converter circuit

Logic circuit

S22

S21

S11

Voff

GND

to Analog_Out

R2

R1

R1

R2

R2=R1

Figure 6 Battery Voltage Detect Circuit