TOP246PN power supply circuit directly with no transformer . How to Repair 110VAC washing machine circuit
Welcome back to authelectronic.com! today we will study a 110VAC Washing machine power supply circuit using TOP246PN directly with no using transformer. If you want to understand more about pulse power supply circuit, please read the articles TNY267PN TNY266PN we put links below.
OR if you want to understand how MCU (microcontroller) in DAIKIN air conditioner circuit work to control IPM, motors,..etc. Please read the article we put link below.
In this 110VAC washing machine circuit, It has two microcontrollers, the first one is main microcontroller, the second one is IPM microcontroller. It controls IPM ( intelligent power module). Therefor, this circuit also has two power supply modules seperately. So in this article we only study the first power supply module using TOP246PN.
Electronic components in circuit
F1 fuse: protect input 100VAC
CR1 varistor : CR1 and F1 fuse to protect input 110VAC input
L1 coil: to filt 110VAC input noise
The second L1 coil: it's a AC voltage detector coil to protect IPM ( Intelligent power module)
IPM: intelligent power module
TOP246PN: power supply IC
R2,R4,R7,R8 : resistors
D3,D4,D5 : diodes
ZD1: zener diode
7805: 5VDC voltage generator IC
How does TOP246PN work in 110AC washing machine circuit?
The 100 VAC input voltage goes through F1 fuse and in a case voltage input OK the impedance of CR1 is nearly infinity . However if input voltage increases suddenly, the impedance of CR1 will be down nearly to zero, so short circuit, the current will flow through F1 fuse and F1 fuse broken and then circuit can be protected.
Then using L1 coil to filter input noise and 110VAC goes to BD1 Bridge rectifier, after that we use C31 C32 capacitors to make output Voltage DC flatter. As you can see another 110VAC line goes through a diode of Bridge rectifer then voltage output will be flatter by C302 capacitor. So Voltage of C301 is Vipm is doubled , ussually it is 280VDC, nearly 300VDC. This 280VDC voltage supply power to IPM (intelligent power module).
The other 110VAC line goes to BD2 bridge rectifier, then output voltage 150VDC will be flatter by using C303 capacitor. This voltage goes to D pin of TOP246PN. Inside TOP246PN has a mosfet , the D pin of TOP246PN is D pin of the mosfet.
This 140VDC also supply power for TOP246PN, inside TOP246PN it has a pulse generator. This pulse generator create a pulse at a certain frequency to G pin of MOSFET inside TOP246PN. Output voltage is depend on frequency and input voltage.
The output voltage is flat by using C2,C3 capacitors and L2 coil, then we have output voltage 12VDC. This 12VDC output is used to supply power for other circuits, relays, sensors,..etc.From 12VDC We use L7805 or78L08 IC to make a 5VDC output voltage , this one is for microcontroller, sensors.
Because of using L2 coil to filter noise so this coil creates a induction voltage opposite to 12VDC output voltage, so we use D4 diode to cancel this induction voltage.
the pin 4 of TOP246PN (Control pin of TOP246PN) is connected to Q52 transistor, Q51 transistor then go back to pin 1 of TOP246PN. Pin 1 is Multi function pin of TOP246PN. This a feedback control circuit to make output voltage 12VDC stable. When the power circuit of this washing machine work normally, we measure voltage of pin 4 TOP246PN is 17.7VDC , Voltage of PIN 1 TOP246PN is 14VDC, voltage of C303 capacitor is 17.7 VDC.