Demonstration Circuit 1922A features the LTC®3129, a high efficiency 200mA buck-boost DC/DC converter with a wide VIN and VOUT range. The DC1922A demo board has two user selectable operating modes: Burst Mode® Operation and Fixed Frequency PWM (JP3). There is also an accurate programmable RUN pin which is used to ENABLE the converter (JP1). The LTC3129 also incorporates a maximum power point control function which can be enabled (JP2) for applications where the input source is a solar cell or is high impedance, such as intrinsically safe applications or high ZOUT thermal electric generators (TEGs).
The DC1922A operates with a 2.42V to 15V input voltage range, and has been designed with the output voltage set to 5.0V. Once the converter is started the LTC3129 can operate with VIN as low as 1.92V provided VCC is backfed. The demo board has optional provisions to backfeed VCC (D1) in order to increase efficiency in some 5V output applications, or to allow operation with VIN down to 1.92V.