5 volt switching power supply using LTC3852
Another simple high efficiency 5 volt DC power supply can be designed using the LTC3852 constant frequency, current mode step-down DC/DC controller which can be powered by an onboard charge pump. Input supplies as low as 2.7V, when doubled by the charge pump, provide 5V to the LTC3852’s control logic and gate drives, supporting a wide selection of logic-level N-channel power MOSFETs.
As you can see in the circuit diagram , this 5 volt DC power supply require few external components . During normal operation, the controller’s top MOSFET is turned on when the clock sets the RS latch, and is turned off when the main current comparator, ICMP , resets the RS latch. The peak inductor current at which ICMP resets the RS latch is controlled by the voltage on the ITH pin, which is the output of the error amplifier EA .
The charge pump section uses a switched capacitor doubler to boost VIN1 to 2 x VIN1, with a regulated maximum of 5V. Regulation is achieved by sensing the output voltage through an internal resistor divider and modulating the charge pump output current based on the error signal. A 2-phase nonoverlapping clock activates the charge pump switches.
The switching regulator section of the LTC3852 can be shut down using the RUN pin. Pulling this pin below 1.1V disables the controller and most of the internal circuitry.
The LTC3852 can be enabled for high efficiency Burst Mode operation, constant frequency pulse skipping mode or forced continuous conduction mode.
This 5 volt switching regulator based on the LTC3852 will provide a 5 volt output voltage at a 10 amperes maximum output current , from an input voltage range between 4 and 36 volts .