Datasheet

VBG

200 mV

Error

Amplifier

CTRL

COMP

TPS61160

TPS61161

SLVS791C –NOVEMBER 2007–REVISED APRIL 2012

www.ti.com

For optimum performance, use the PWM dimming frequency in the range of 5kHz to 100kHz. The requirement of

minimum dimming frequency comes from the EasyScale detection delay and detection time specification in the

dimming mode selection. Since the CTRL pin is logic only pin, adding an external RC filter applied to the pin

does not work.

Figure 14. Block Diagram of Programmable FB Voltage Using PWM Signal

To use lower PWM dimming, add an external RC network connected to the FB pin as shown in the additional

typical application (Figure 19).

DIGITAL 1 WIRE BRIGHTNESS DIMMING

The CTRL pin features a simple digital interface to allow digital brightness control. The digital dimming can save

the processor power and battery life as it does not require a PWM signal all the time, and the processor can

enter idle mode if available.

The TPS61160/1 adopts the EasyScale™ protocol for the digital dimming, which can program the FB voltage to

any of the 32 steps with single command. The step increment increases with the voltage to produce pseudo

logarithmic curve for the brightness step. See the Table 1 for the FB pin voltage steps. The default step is full

scale when the device is first enabled (V

= 200 mV). The programmed reference voltage is stored in an internal

EasyScale™: 1 WIRE DIGITAL DIMMING

EasyScale is a simple but flexible one pin interface to configure the FB voltage. The interface is based on a

master-slave structure, where the master is typically a microcontroller or application processor. Figure 15 and

Table 2 give an overview of the protocol. The protocol consists of a device specific address byte and a data byte.

The device specific address byte is fixed to 72 hex. The data byte consists of five bits for information, two

address bits, and the RFA bit. The RFA bit set to high indicates the Request for Acknowledge condition. The

Acknowledge condition is only applied if the protocol was received correctly. The advantage of EasyScale

compared with other on pin interfaces is that its bit detection is in a large extent independent from the bit

transmission rate. It can automatically detect bit rates between 1.7kBit/sec and up to 160kBit/sec.

Product Folder Link(s): TPS61160 TPS61161