PWM CONTROL 2A STEP-DOWN CONVERTER
UTC P1885 consists of 2A step-down switching regulator
control which includes a reference voltage source, oscillation
circuit, error amplifier, internal PMOS and etc with PWM.
UTC P1885 can provide low-ripple power, high efficiency, and
excellent transient characteristics and an enable function, an over
current protect function and a short circuit protect function are
built inside, so the operation frequency will be reduced from
300KHz to 30KHz when OCP or SCP happens. And the PWM
control circuit can vary the duty ratio linearly from 100 down to
0%. This converter also includes an error amplifier circuit as well
as a soft-start circuit that prevents overshoot at startup. Also, to
minimum external component count an internal compensation block is built in.
These ICs can work as step-down switching regulators with the
addition of an internal P-channel Power MOS, a coil, capacitors,
and a diode connected externally. They provide such outstanding
features: low current consumption. It is also suitable for the
operation via an AC adapter because this converter can accommodate an input voltage up to 23V.
* Soft-start, Current Limit, Enable function
* Thermal Shutdown function
* Built-in internal SW P-channel MOS
* Input voltage: 3.6V to 23V.
* Output voltage: 0.8V to VCC.
* Duty ratio: 0% to 100% PWM control
* Oscillation frequency: 300KHz typ.
TYPICAL APPLICATION CIRCUIT