log

_

450

450

22

ic

PG

low

V

V

R

W ´

=

W +

(1)

_

log

22 (1

)

PG high

ic

out

V

V

R

A

I

m

=

-

´

+

(2)

Setting the Delay Times DLY1, DLY2

DLY

th

5 A

DLY

5 A

DLY

C

=

=

, with DLY = Desired delay time

V

1.24 V

m

´

m

´

(3)

DLY

5

A

2.5 ms

C

=

= 10.1 nF

CDLY = 10 nF

1.24 V

m

´

Þ

(4)

Boost Converter

TPS65166

maximum switch leakage current of 1

µA the minimum PG output voltage can be calculated as following:

Recommended are R22 values between 5k

Ω and 500kΩ. Typical value for R22 is 10kΩ.

Connecting an external capacitor to the DLY1 and DLY2 pins sets the delay time. The capacitor is charged with

a constant current source of typically 5

µA. The delay time is terminated when the capacitor voltage has reached

calculated as follows:

Example for setting a delay time of 2.5ms:

The non-synchronous current mode boost converter operates in Pulse Width Modulation (PWM) operation with a

fixed frequency of 750 kHz. For maximum flexibility and stability with different external components the converter

uses external loop compensation. At start up the boost converter starts with an externally adjustable soft-start.

The boost converter provides the supply voltage for the LCD source driver as well as for the charge pump

converter. No feed-forward capacitor is needed for proper operation.

18

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