understanding top223p and pq05rd11 ic in thompson dvd power supply

by:HoldPeak     2020-04-13
The TOP223P pulse width modulation ic is designed to work in a switching mode power supply (smps).
It is mainly used for audio/video electronic devices.
This ic is rarely used by computer monitors.
In this article, what I would like to share with you is that not all switch mode power transformers must use a combination of uc3842 and power or chopper fet to work properly.
The design of the SMPS is now becoming more and more compact, and this TOP223P ic is actually composed of oscillator circuits and power fet integrated into it.
Therefore, do not search the power fet in the surrounding circuit.
If you look at this photo of the Thompson DTH5008FEK power supply, you will notice that there are not many components in the main section.
What you see is the coupling of the fuse, bridge rectifier, filter capacitor, top223p ic, optical isolator and diodes, resistors and capacitors.
You won\'t spend much time fixing this type of power failure.
Some top switch ICs have only three terminals, but there are 8 pins in this type.
The secondary part consists of a fast recovery diode, a filter capacitor, a coil, and a voltage regulator ic with two part numbers pq 05rd11.
Both of these ICs are universal low power-
Loss voltage regulator with 1 amp output.
Usually the voltage regulator has 3 pins, but there are 4 pins in this type.
Additional pins are used for on/off control functions.
The pin output function of this ic is pin 1 = DC input (vin)
, Pin 2 = DC output (vout)
, Pin 3 = ground, pin 4 = on/off control terminal (vc).
If you want to solve the power problem successfully, it is important to know the specifications of this type of ic.
Here are the specifications for this type of home ic PQ03RD13 = 3.
3 V output, PQ05RD11 = 5 V output, PQ09RD11 = 9 V output, PQ012RD11 = 12 V output.
By measuring the output of this ic pin, you will have a rough number regardless of whether the power supply works or not.
For example, when you put the Red probe of the meter on pin 2 of this Powered pq 05rd11 ic, you should expect 5 volts.
If the output voltage is only 2-
3 V, then suspect the problem of low DC input voltage, fault of voltage regulator, high esr Ohms in filter capacitor, and even bad components where the line is further away. Conclusion-
If you understand how the power supply works and you have a schematic diagram of a particular device, it is very easy to troubleshoot a power failure using a TOP223P ic or other home type.
Below is a schematic diagram of the 20-watt universal input power supply using the TOP224P ic.
In a word, make sure you have to know how to check all the electronic components before repairing them.
If you are not sure how to test basic electronic components, I strongly recommend that you check all the pages on my website --www.
Guide to Electronic Maintenance.
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