High-speed parallel voltage-stabilized power supply circuit diagram

As shown in the figure, this is a parallel-adjustable voltage-stabilized power supply with the characteristics of high speed, low noise and low internal resistance. It is very effective in supplying power to HiFi circuits. In terms of noise, the detail and extension of music, it is unmatched by the series-connected voltage-stabilized power supply.

LM317 and 22Ω resistor form a constant current circuit with a constant current value of 560mA, providing the total current of the entire loop. The junction field effect tube 2SK30 provides a constant current for the light-emitting diode, and a stable reference voltage with very low noise is obtained at both ends of the light-emitting tube. The operational amplifier LM74l forms a voltage comparator, which compares the voltage obtained from the sampling network with the reference voltage, controls the current of the shunt tube 3DDl5, and thus keeps the output voltage constant at a certain set value.

The circuit uses common general components, but there are a few things to note:

(1) The constant current of 2SK30 is about 3-6mA, and it is required to be paired up and down, and the parameter values ​​are as consistent as possible.
(2) The light-emitting diodes VD1 and VD2 are Φ5mm, and the voltage drop is 1.6-1.65V, and they are also required to be paired up and down.
(3) The β value of 3DDl5 should be as large as possible, preferably greater than 60, and the heat sink should also be large enough.
(4) The sampling network resistors R5-R8 must ensure stability.
(5) The power of the transformer used should not be less than 40W. It is more ideal to use a toroidal transformer.