M61048FP

Rev.1.00 Mar 04, 2005 page 11 of 23

Block Diagram Description

Battery Voltage Detection Circuit

The M61048FP battery voltage detection circuit is shown in Figure 3. This circuit is composed of switch, buffer

amplifier, reference voltage section and logic circuit.

Microcomputer selects detecting voltage before logic circuit controls the connection of switches. This connection

decides which cell voltage (Vbat1, Vbat2, Vbat3, Vbat4) should be output from Analog out pin. Besides offset voltage

can be output.

In Power Down mode, supply current in this block is close to zero because all switches are off.

Note: Regard 100

µs as the standard of settling time by voltage change in this block.

–

+

Logic circuit

VREF

VIN1

VIN2

VIN3

VBAT1

S11

S21

S22

S32

From Serial to Parallel

conversion circuit

Switch control

To Multiplexer circuit

S31

S42

S41

VIN4

GND

S02

S01

VBAT2

VBAT3

VBAT4

Figure 3 Battery Voltage Detection Circuit

Table 1

Turned on Switches

Function

Turn on Switch (refer to Figure 3)

VBAT1_OUTPUT

S11, S22

VBAT2_OUTPUT

S21, S32

VBAT3_OUTPUT

S31, S42

VBAT4_OUTPUT

S41, S02

VBAT1_OFFSET

S21, S22

VBAT2_OFFSET

S31, S32

VBAT3_OFFSET

S41, S42

VBAT4_OFFSET

S01, S02