7513 datasheet(41/66 Pages) RENESAS

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SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

MITSUBISHI MICROCOMPUTERS

7513 Group

Voltage Multiplier (3 Times)

The voltage multiplier performs threefold boosting. This circuit in-

puts a reference voltage for boosting from LCD power input pin

VL1. (However, when using a 1/2 bias, connect VL1 and VL2 and

apply voltage by external resistor division.)

Set each bit of the segment output enable register and the LCD

mode register in the following order for operating the voltage mul-

tiplier.

1. Set the segment output enable bits (bits 0 to 5) of the seg-

ment output enable register to “0” or “1.”

2. Set the duty ratio selection bits (bits 0 and 1), the bias con-

trol bit (bit 2), the LCD circuit divider division ratio selection

bits (bits 5 and 6), and the LCDCK count source selection

bit (bit 7) of the LCD mode register to “0” or “1.”

3. Set the LCD output enable bit (bit 6) of the segment output

enable register to “1.”

4. Set the voltage multiplier control bit (bit 4) of the LCD mode

When voltage is input to the VL1 pin during operating the voltage

multiplier, voltage that is twice as large as VL1 occurs at the VL2

pin, and voltage that is three times as large as VL1 occurs at the

VL3 pin.

When using the voltage multiplier, apply 1.3 V

≤ Voltage ≤ 2.3 V to

the VL1 pin.

When not using the voltage multiplier,apply proper voltage to the

LCD power input pins (VL1–VL3). Then set the LCD output enable

bit to “1.”

When the LCD output enable bit is set to “0,” the VCC voltage is

applied to the VL3 pin inside of this microcomputer.

The voltage multiplier control bit (bit 4 of the LCD mode register)

controls the voltage multiplier.

Fig. 42 Example of circuit at each bias

Table 10 Bias control and applied voltage to VL1–VL3

Bias value

1/3 bias

Voltage value

VL3=VLCD

VL2=2/3 VLCD

VL1=1/3 VLCD

Note: VLCD is the maximum value of supplied voltage for the LCD panel.

Bias Control and Applied Voltage to LCD

Power Input Pins

To the LCD power input pins (VL1–VL3), apply the voltage shown

in Table 10 according to the bias value.

Select a bias value by the bias control bit (bit 2 of the LCD mode

1/2 bias

VL3=VLCD

VL2=VL1=1/2 VLCD

VL3

VL2

VL1

1/3 bias

when using the voltage multiplier

VL3

VL2

VL1

1/3 bias

when not using the voltage multiplier

Open

R1=R2=R3

Contrast control

VL3

VL2

VL1

1/2 bias

Open

R4=R5

Contrast control

VCC

PXX

7513 Datasheet(PDF) 41 Page - Renesas Technology Corp

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