Datasheet

CTRL
Low
High
V
DD
t
off
t
store
t
low
t
high
t
set
V
SS
t
ss
t
init
CTRL
Low
High
t
ss
t
off
t
init
V
DD
V
ss
TPS65137
www.ti.com 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.
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