Datasheet

TPS65735
www.ti.com SLVSAI6–JUNE 2011
Table 2-4. Scaling Resistors for COMP Pin Function
(V
VLDO
= 2.2 V)
Scaling Resistors for COMP Pin
Value
Function
R
BSCL1
3.0 MΩ
R
BSCL2
2.36 MΩ
Table 2-5. Scaling Resistors for COMP Pin Function
(V
VLDO
= 3.0 V)
Scaling Resistors for COMP Pin
Value
Function
R
BSCL1
3.0 MΩ
R
BSCL2
2.48 MΩ
Using the designed values in Table 2-4 or Table 2-5, the voltage on the COMP pin will be: V
COMP
= 0.5 ×
V
VLDO
+ 300 mV. This assures that the COMP pin voltage will be close to half of the LDO output voltage
plus the LDO dropout voltage of the device. The COMP pin can also be used as the input to an ADC
channel of an external microcontroller if greater accuracy or more functionality is desired than a simple
comparison.
2.11.3 SW_SEL Pin Functionality
The SW_SEL pin is used to select what type of switch is connected to the SWITCH pin of the device.
Selection between a push-button and a slider switch can be made based on the state of this pin.
Table 2-6. SW_SEL Settings
SW_SEL State Type of Switch Selected
Low
Slider Switch
(V
SW_SEL
< V
IL(PMIC)
)
High
Push-button
(V
SW_SEL
> V
IH(PMIC)
)
When the push button switch type is selected, the device will debounce the SWITCH input with a 32 ms
timer for both the ON and OFF events and either power on or off the device. Using the push-button switch
function, the on and off timings are equal; t
ON
= t
OFF
. If the system requirements are such that the on and
off timings should be different, t
ON
≠ t
OFF
, then refer to the following section for the correct system setup:
Section 3.4. When the slider switch operation is selected, the SWITCH pin must be externally pulled up to
the SYS voltage with a resistor and the output connected to the slider switch. When the SWITCH pin is
pulled to ground, the device will turn on and enter the power up sequence.
2.11.4 SWITCH Pin
The SWITCH pin behavior is defined by the SW_SEL pin (Section 2.11.3) which defines the type of switch
that is connected to the system; either a slider switch or push-button.
2.11.5 Slider Switch Behavior
If a slider switch is connected in the system then the system power state and VLDO output (which can
power an external MCU) is defined by the state of the slider switch. If the slider is in the "off" position than
the SWITCH pin should be connected to the SYS pin. If the slider is in the "on" position than the SWITCH
pin should be connected to ground. Figure 2-15 details the system operation using the slider switch
configuration.
Copyright © 2011, Texas Instruments Incorporated POWER MANAGEMENT CORE 23
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