Introduction
1
Introduction
1.1
TPS62737 IC Features
The TPS62737 is a highly integrated ultra low power buck converter solution that is well suited for meeting
the special needs of ultra low power applications such as energy harvesting. The TPS62737 provides the
system with an externally programmable regulated supply in order to preserve the overall efficiency of the
power management stage versus a linear step down converter. Although intended to have input power
from an energy storage element such as a Li-Ion battery or super cap, the TPS62737 can accept any
input voltage up to 5.5 V, while supplying the rail to low voltage electronics.
The TPS62737 integrates an optimized hysteretic controller for low power applications. The internal
circuitry utilizes a time based sampling system in order to reduce the average quiescent current. This
allows for the quiescent current consumption to scale with output load levels. The regulated output has
been optimized to provide high efficiency across low output currents (< 10 µA) to high currents (200 mA).
To further assist users in the strict management of their energy budgets, the TPS62737 toggles the input
good (VIN_OK) flag to signal an attached microprocessor when the voltage on the input supply has
dropped below a pre-set critical level. The intent of VIN_OK is to trigger the reduction of load currents to
prevent the system from entering an undervoltage condition. Two separate enable signals allow the user
to enable/disable the regulated output or place IC into an ultra-low quiescent sleep state. Two separate
enable signals allow the enabling or disabling of the regulated output or allow putting the IC into an ultra-
low quiescent sleep state.
The output voltage regulation point and input good threshold are set by external resistors.
In order to
maximize efficiency at light load, the use of voltage level setting resistors > 1 M
Ω
is recommended.
However, during board assembly or modification, contaminants such as solder flux and even
some board cleaning agents can leave residue that may form parasitic resistors across the
physical resistors and/or from one end of a resistor to ground, especially in humid, fast airflow
environments. This can result in the voltage regulation and threshold levels changing significantly
from those expected per the installed resistor values. Therefore, the boards must be carefully
cleaned then rinsed with de-ionized water until the ionic contamination of that water. If this is not
feasible, then it is recommended that the sum of the voltage setting resistors be reduced.
1.2
TPS62737EVM Features
1. Input voltage range from 2.0 V to 5.5 V
2. Output voltage set to 1.8 V but adjustable from 1.3 V to 5.3 V with external resistors
3. VIN_OK threshold of 2.9 V but adjustable from VOUT to 5.3 V with external resistors
4. Easily accessible headers for IN, IN-SENSE, OUT, OUT-SENSE, GND, VIN_OK
5. Jumpers for EN1 and EN2
2
Evaluation Module for TPS62737 Ultra Low Power Buck Converter
SLVU939A – July 2013 – Revised August 2014
Copyright © 2013–2014, Texas Instruments Incorporated
