4556 datasheet(47/145 Pages) RENESAS

47 / 145 page

Rev.3.02

Dec 22, 2006

page 47 of 142

REJ03B0025-0302

4556 Group

(5) LCD power supply circuit

Select the LCD power supply circuit suitable for the using LCD

panel.

The LCD power supply circuit is fixed by the followings;

• The internal dividing resistor is controlled by bit 0 of register L2.

• The internal dividing resistor is selected by bit 3 of register L1.

• The bias condition is selected by bits 0 and 1 of register L1.

qInternal dividing resistor

The 4556 Group has the internal dividing resistor for LCD power

supply.

When bit 0 of register L2 is set to “0”, the internal dividing resis-

tor is valid. However, when the LCD is turned off by setting bit 2

of register L1 to “0”, the internal dividing resistor is turned off.

The same six resistor (r) is prepared for the internal dividing re-

sistor. According to the setting value of bit 3 of register L1 and

using bias condition, the resistor is prepared as follows;

• L13 = “0”, 1/3 bias used: 2r ✕ 3 = 6r

• L13 = “0”, 1/2 bias used: 2r ✕ 2 = 4r

• L13 = “1”, 1/3 bias used: r ✕ 3 = 3r

• L13 = “1”, 1/2 bias used: r ✕ 2 = 2r

qVLC3/SEG0 pin

The selection of VLC3/SEG0 pin function is controlled with the bit

3 of register L2.

When the VLC3 pin function is selected, apply voltage of VLC3 <

VDD to the pin externally.

When the SEG0 pin function is selected, VLC3 is connected to

VDD internally.

q VLC2/SEG1, VLC1/SEG2 pin

The selection of VLC2/SEG1 pin function is controlled with the bit

2 of register L2.

The selection of VLC1/SEG2 pin function is controlled with the bit

1 of register L2.

When the VLC2 pin and VLC1 pin functions are selected and the

internal dividing resistor is not used, apply voltage of

0<VLC1<VLC2<VLC3 to these pins. Short the VLC2 pin and VLC1

pin at 1/2 bias.

When the VLC2 pin and VLC1 pin functions are selected and the

internal dividing resistor is used, the dividing voltage value gen-

erated internally is output from the VLC1 pin and VLC2 pin. The

VLC2 pin and VLC1 pin have the same electric potential at 1/2 bias.

When SEG1 and SEG2 pin functions are selected, use the inter-

nal dividing resistor. In this time, VLC2 and VLC1 are connected to

the generated dividingg voltage.

Fig. 36 LCD power supply circuit example (1/3 bias condition selected)

VLC3

VLC2

VLC1

SEG0

SEG1

SEG2

VLC3

VLC2

VLC1

VLC3

SEG1

SEG2

a) Register L2=(0000)2

b) Register L2=(1000)2

VLC3

VLC2

VLC1

VLC3

VLC2

VLC1

VLC3

VLC2

VLC1

c) Register L2=(1110)2

d) Register L2=(1111)2

VLC3

VLC2

VLC1

4556 Datasheet(PDF) 47 Page - Renesas Technology Corp

4556 Datasheet(HTML) 47 Page - Renesas Technology Corp

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL