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APPLICATION INFORMATION

TYPICAL APPLICATION OF A SMART PHONE DISPLAY WITH RESISTORS CONNECTED IN

VIN

C1+

C1−

C2+

C2−

EN1

EN2

GND

VOUT

D1

D2

D3

D4

D5

ISET

0.47 mF

0.47 mF

1 mF

1 mF

VIN = 2.7 V

to 6.5 V

Typical Smartphone Display

PGND

ANALOG DIMMING USING ISET PIN

VIN

C1+

C1−

C2+

C2−

EN1

EN2

GND

VOUT

D1

D2

D3

D4

D5

ISET

0.47 mF

0.47 mF

1 mF

1 mF

VIN = 2.7 V

to 6.5 V

6 kW

V = 0 mV to

600 mV

PGND

TPS60230

SLVS516A – MAY 2004 – REVISED JUNE 2004

PARALLEL

If more than 25 mA of output current is needed, then the input pins to the current sinks can be connected in

parallel as shown in the following application figure. This method can also be used to connect a LC display with

only two connections for the white LEDs.

Figure 12. Typical Application With Resistors in Parallel

The ISET pin can be used to connect an analog dc signal in the range of 0 mV to 600 mV (EN1 = EN2 = 1) for

analog dimming of the white LEDs. For an input voltage of 0 V at ISET, the current is at its maximum, whereas at

600 mV, the LED current is zero. The maximum current is:

•

For EN2 = EN1 = 1: ILED = Vset/Rset

× K = 0.6V/6kR × 270 = 27 mA per LED

•

For EN2 = 1, EN0 = 1: ILED = Vset/Rset

× K = 0.4V/6kR × 270 = 18 mA per LED

•

For EN2 = 0, EN1 = 1: ILED = Vset/Rset

× K = 0.2V/6kR × 270 = 9 mA per LED

•

With EN2, EN1 set to 10 or 01, a voltage of 400 mV or 200 mV is required to set the LED current to zero.

Figure 13. Analog Dimming Connections Using ISET Pin

12