hd66765 Renesas Electronics Corporation., hd66765 Datasheet - Page 64

• Manufacturer Part Number: hd66765
• Description: 396-channel Segment Driver With Internal Ram For 4096-color Displays - Hitachi Semiconductor
• Manufacturer: Renesas Electronics Corporation.

HD66765
Oscillation Circuit
The HD66765 can oscillate between the OSC1 and OSC2 pins using an internal R-C oscillator with an
external oscillation resistor. Note that in R-C oscillation, the oscillation frequency is changed according
to the external resistance value, wiring length, or operating power-supply voltage. If Rf is increased or
power supply voltage is decrease, the oscillation frequency decreases. For the relationship between Rf
resistor value and oscillation frequency, see the Electric Characteristics Notes section.
When using the HD66765 with the HD66764 common driver, the relationship between the SEG and
COM output levels is as shown in the following figure. The LCD drive level (VSH, VSL) which is used
by the HD66765 is supplied from the HD66764 common driver. While the display is off, SEG and COM
outputs go to GND level.
Rf
2) External Resistance Oscillation Mode
VSL (GND)
Figure 49 Relationship with SEG/COM Output Level
VCH
VSH
VCL
OSC1
OSC2
VM
HD66765
M
(200 KHz)
1) External Clock Mode
Clock
Figure 48 Oscillation Circuits
Lit
resistance (2 k )
No lit
Note: The Rf resistance must be located near
Damping
Lit
COM waveform
the OSC1/OSC2 pin on the chip.
64
OSC1
OSC2
HD66765
No lit
Lit
No lit
SEG waveform