CTRL

Low

High

CTRL

Low

High

TPS65137

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SLVS929A – MAY 2010 – REVISED OCTOBER 2012

ENABLE (CTRL pin)

The CTRL pin serves two functions. One is the enable and disable of the device, the other is the output voltage

programming of the device. If the digital interface is not required the CTRL pin can be used as a standard enable

pin for the device. Pulling CTRL high starts the converter operating with its default output voltage on OUTN of

–4.93V.

DIGITAL INTERFACE (CTRL)

The digital interface allows programming the negative output voltage OUTN in digital steps. If the digital output

voltage setting is not required then the CTRL pin can also be used as a standard enable pin. In such a case the

device will come up with its default output voltage of OUTN of –4.93V.

Figure 15. CTRL Used as a Standard Device Enable

The digital output voltage programming of OUTN is implemented by a simple digital interface with the timing

shown in Figure 16.

Figure 16. Digital Interface Using CTRL

Once CTRL is pulled high the device will come up with its default voltage of –4.93V. The TPS65137 has a 5 bit

DAC implemented with the correspondent output voltage as given in Table 1. The interface counts the rising

edges applied to CTRL pin once the device is enable. For example with the timing diagram shown in Figure 16,

OUTN is programmed to –4.93V since 4 rising edges are applied. Other output voltages are programmed

according to Table 1.

Copyright © 2010–2012, Texas Instruments Incorporated

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