Datasheet

TPS62400, TPS62401
TPS62402, TPS62403, TPS62404
www.ti.com SLVS681E –JUNE 2006–REVISED APRIL 2010
Table 1. Addressable Registers for default Fixed Output Voltage Options (PIN DEF_1 = digital input)
DEVICE REGISTER DESCRIPTION DEF_1 A1 A0 D4 D3 D2 D1 D0
PIN
REG_DEF_1_High Converter 1 output voltage setting for High 0 1 Output voltage setting, see
DEF_1 = High condition. The content of Table 4
the register is active with DEF1_ Pin high.
TPS62401,
REG_DEF_1_Low Converter 1 output voltage setting for Low 0 0 Output voltage setting, see
TPS62402,
DEF_1 = Low condition. Table 4
TPS62403,
TPS62404
REG_DEF_2 Converter 2 output voltage Not 1 0 Output voltage setting, see
applicable Table 6
Don’t use 1 1
Table 2. Addressable Registers for Adjustable Output Voltage Options (PIN DEF_1 = analog input)
DEVICE REGISTER DESCRIPTION A1 A0 D4 D3 D2 D1 D0
REG_DEF_1_High not available
REG_DEF_1_Low Converter 1 output voltage setting 0 0 see Table 5
TPS62400
REG_DEF_2 Converter 2 output voltage 1 0 see Table 6
Don’t’ use 1 1
Bit Decoding
The bit detection is based on a PWM scheme, where the criterion is the relation between t
LOW
and t
HIGH
. It can
be simplified to:
High Bit: t
High
> t
Low
, but with t
High
at least 2x t
Low
, see Figure 34
Low Bit: t
Low
> t
High
, but with t
Low
at least 2x t
High
, see Figure 34
The bit detection starts with a falling edge on the MODE/DATA pin and ends with the next falling edge.
Depending on the relation between t
Low
and t
High
a 0 or 1 is detected.
Acknowledge
The Acknowledge condition is only applied if:
• Acknowledge is requested by a set RFA bit
• The transmitted device address matches with the device address of the device
• 16 bits were received correctly
In this case, the device turns on the internal ACKN-MOSFET and pulls the MODE/DATA pin low for the time
t
ACKN
, which is 520ms maximum . The Acknowledge condition is valid after an internal delay time t
valACK
. This
means the internal ACKN-MOSFET is turned on after t
valACK
, when the last falling edge of the protocol was
detected. The master controller keeps the line low during this time.
The master device can detect the acknowledge condition with its input by releasing the MODE/DATA pin after
t
valACK
and read back a 0.
In case of an invalid device address, or not-correctly-received protocol, no-acknowledge condition is applied;
thus, the internal MOSFET is not turned on and the external pullup resistor pulls MODE/DATA pin high after
t
valACK
. The MODE/DATA pin can be used again after the acknowledge condition ends.
NOTE
The acknowledge condition may only be requested in case the master device has an open
drain output.
In case of a push-pull output stage it is recommended to use a series resistor in the MODE/DATA line to limit the
current to 500 mA in case of an accidentally requested acknowledge, to protect the internal ACKN-MOSFET.
MODE Selection
Because the MODE/DATA pin is used for two functions, interface and a MODE selection, the device needs to
determine when it has to decode the bit stream or to change the operation mode.
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