M62295 Просмотр технического описания (PDF) - MITSUBISHI ELECTRIC

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M62295

PC BACK- LIGHT CONTROL IC LCD BACK-LIGHT CONTROL IC

MITSUBISHI ELECTRIC  

MITSUBISHI(Standard Linear ICs)

M62295GP

PC BACK- LIGHT CONTROL IC

Function description

• Output oscillation circuit and tooth-wave generating circuit for light control (RT, CT1, CT2)

As shown in Fig.1, charge/discharge current

for each oscillation circuit is set by connecting

resistors to RT terminal.

RT terminal is connected to FB terminal by

resistor to control the frequency for light control.

CT1 is the terminal for connecting capacitor for

output oscillation circuit, generating triangular-

wave oscillating between lower limit (approx. 0.25V)

and upper limit (approx. 1.25V) by the charge

current set at RT terminal.

CT2 is the terminal for connecting capacitor for

tooth-wave for light control, into which one twentieth

of charge current of CT1 terminal flows generating

tooth-wave oscillating between lower limit (approx.

0.25V) and upper limit (approx. 1.25V).

Each charge current and oscillation frequency is

decided by the formula shown below.

RT (1.25V)

CT1

CT2

FB

Ro

CT1

CT2

Fig.1 Connections of RT,CT1, CT2

CT1 charge/ discharge current = 1.25

(ICT1charge)

Ro

CT2 charge/ discharge current

(ICT2charge)

=

1.25 1

Ro * 20

CT1

G1

(POUT)

1.25V

0.8V

0.7V

T

0.25V

Output freq. (Fosc) = 1 =

1

T

2

CT1 * ICT1charge

1

Tooth - wave freq. (CT2osc) =

CT2

*

1

ICT2charge

G2

(NOUT)

CT2

1.25V

0.25V

Tooth - wave freq. (CT2osc) (divided ratio) =

Output freq. (Fosc)

CT1

CT2 * 10

Fig.2 Waveform for CT1, CT2, and G1, G2

• ON/OFF control function (P/C)

ON/OFF control is available using P/C terminal.

As shown in Fig.3, ON/OFF control is made by

connecting P/C terminal to Vcc or GND or by making

P/C terminal open.

P/C = Vcc : IC in normal operation mode

P/C = GND&OPEN : IC operation at halt

Vcc

P/C

Fig.3 Connection example for P/C

(4/7)

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