Demonstration circuit 2585A contains two circuits featuring the LTC3290. The top LTC3290 circuit operates as a high voltage boost by using the power from two input supplies to create a higher output voltage. The bottom LTC3290 circuit operates as a VIN tracking supply by using the power from an auxiliary supply input (VAUX) and regulating a voltage above the VIN supply input. The wide VIN/VAUX range allows two voltages to be used together to efficiently create a third voltage, boost from a single supply to boost, or regulate above a variable input voltage like a battery.
The high efficiency boost circuit has three selectable outputs, 15V, 24V, or 42V. If a different output is desired then the top resistor, R2, and/or the bottom resistor, R6, can be changed to provide a different output voltage. Refer to the LTC3290 data sheet and demo board schematic for more information on how to set the output voltage for the LTC3290.
The VIN tracking circuit also has three selectable outputs, VIN2 + 5V, VIN2 + 10V, and VIN2 + 15V. If a different output voltage is desired, then R9 and/or R13 can be changed to set a different output. Refer to the LTC3290 data sheet for more information on how to set the output voltage in VIN tracking mode.
The LTC3290 can use two separate supplies or a single supply connected to both inputs for either circuit. This can be useful to boost or track a battery voltage with a regulated output.
The LTC3290 data sheet gives a complete description of the device, operation and application information. The data sheet must be read in conjunction with this demo manual.