Changes in DC power output
DC power supply is a commonly used electronic device that can ensure stable voltage output in the event of voltage fluctuations or load changes in the power grid. A low ripple, high-precision voltage regulator has important practical application value in the fields of instrumentation, industrial control, and measurement. This design uses two sets of 17.5V AC windings output by transformers, and three sets of regulated power supplies are designed, of which two sets are adjustable from 3V to 15V, and the other set has a fixed output of+5V; The rated working current is 1.2A and it has a "+" and "-" step voltage regulation function, with a small step of 0.12V and a ripple factor of no more than 4%. And it is equipped with a digital potentiometer X9318 to adjust the variation of the unit reference voltage to form a high reliability, small ripple, and high-precision voltage controlled DC adjustable voltage regulator hardware circuit and microcontroller control.
form:
1. The power transformer converts 220V, 50Hz AC voltage into a low-voltage AC voltage that is roughly equivalent to the output DC voltage.
2. The rectifier circuit utilizes the unidirectional conductivity of diodes to convert low-voltage AC power into unidirectional pulsating voltage, which can be divided into half wave and full wave rectification.
3. The filtering circuit utilizes the impedance characteristics of inductance and capacitance to filter out the AC component in the rectified unidirectional pulsating current, converting it into smooth DC current.
4. When the voltage of the power grid fluctuates or the load changes, the DC power obtained on the load will be unstable, affecting the performance of electronic devices. A voltage regulator is used, which adopts some negative feedback methods to automatically adjust the unstable factors and obtain a stable voltage.
Basic Requirements
① Design three sets of regulated power supplies using two sets of 17.5V AC windings output by transformers, with two sets of adjustable 3V-15V and the other set of fixed output+5V;
② Output current of each group * large: 750 mA;
③ When the efficiency of each group is greater than 75% and measured under 500mA output conditions, a current measurement terminal should be reserved at the DC/DC input terminal;
④ To achieve program control, reserve MCU control interfaces.
The output of a DC power supply is not constant. For example, when the DC power supply operates in a constant voltage state, its output voltage may vary slightly due to changes in input voltage or load. When the DC power supply operates in a constant current state, its output current may also vary slightly due to changes in input voltage or load.
