I2C Programmable 5A Step-Down Converter
Created: Mar 01, 2017
No description available.
This reference design is a 5A step-down converter that has an I2C-programmable output. This design controls the output voltage and also enables special power-saving modes operation. This design uses MIC24045, which is an I2C programmable, high-efficiency, wide-input range, and 5A synchronous step-down regulator. For the MIC24045 device, the user can program via I2C, various parameters such as output voltage, switching frequency, soft-start slope, margining, current limit values and start-up delay. Programmability is achieved by means of an I2C-compatible serial digital interface, which can support Serial Clock (SCL) rates up to 400 kHz (fast mode). The MIC24045 wide switching frequency adjustment range, valley current-mode control technique, high-performance error amplifier and external compensation allow the best trade offs between high-efficiency and small solution size.
This design accepts voltage supply that ranges from 4.5V to 19V and outputs voltage from 0.64V to 5.25V in 5mV, 10mV, 30mV and 50mV steps at 5A. Additionally, an on-board load transient generator circuit and connections for loop gain measurements are provided. A connector matching the MCP2221 breakout module I2C interface is provided for board compatibility with I2C. This circuit requires only a single power supply with at least 5A current capability. The MIC24045 has an internal VDDA LDO, so no external linear regulator is required to power the internal biasing of the device. The MIC24045 does not require a separate supply for the I2C interface and for the internal logic registers, which are all powered from the VDDA rail.
The circuit only requires a minimal amount of external components. Only the inductor, supply decoupling capacitors and compensation network are external. The flexibility in the external compensation design allows the user to optimize their design. This is well suited to be used in many portable devices that must vary the core voltage of the applications processor dynamically.