Datasheet

Evaluation With the TPS6112x EVM
2-2
2.1 Evaluation With the TPS6112x EVM
This chapter details the evaluation process and features of the EVM. For this
evaluation, a load is connected to the output terminal in order to adjust the load
current between 0 mA and 250 mA.
For accurate output voltage and input voltage measurements, it is important
to measure the voltage on the input and output voltage terminals with Kelvin
contacts or with a voltmeter connected directly to the input voltage or output
voltage terminals. This eliminates any measurement errors related to voltage
drops along the input and output terminal wires connected to the power supply
or load.
2.1.1 Enable (EN) Jumper
This jumper is used to enable the device. Connecting the enable pin (EN) to
V
BAT
enables the part. The device is disabled when EN is set to GND. For more
details refer to the data sheet.
2.1.2 LDO Enable (LDOEN) Jumper
This jumper is used to enable the integrated LDO of the device. Connecting
the LDO enable pin (LDOEN) to V
LDOIN
enables the LDO section of the part.
Disabling the integrated LDO can be done by setting this jumper to GND.
2.1.3 Power Save Mode Enable (SKIPEN) Jumper
This jumper enables the device to enter into power save mode at light load,
when it is set to V
BAT
. The device automatically stops switching when the
output voltage reached its upper threshold, and starts switching again, when
the lower threshold of the output voltage is reached.
When disabling the power save function by setting the jumper to GND, the
device stays operating in fixed frequency mode, regardless of the load current
value. In this mode, however reverse current flows back to the input during light
load operation, increasing power losses. The operating frequency stays
constant, which implies low output voltage ripple.
2.1.4 LBI/LBO Comparator
The LBO terminal is an open drain output and has a pullup resistor, R7,
connected to the output. The signal on this pins can go low as soon as the input
voltage at LBI falls below the threshold of 500 mV. Refer to the more detailed
description in the data sheet. The LBO output stays at high-impedance when
the input voltage at LBI is above the appropriate threshold. A resistor divider
(R1, R2) is used on the EVM to monitor the supply voltage.
More details about setting the low battery threshold voltage can be found in
the data sheet (literature number SLVS427).
2.1.5 Power Good Output
The PG pin is an open drain output with a pullup resistor, R9, connected to the
output. The signal on this pin goes high as soon as the output voltage is greater
than typically 92% of the nominal voltage. The signal goes low as soon as the
output voltage falls below this typical threshold. There is an implemented delay
time of 30 µs to prevent the power good output from ringing.