Air purifier - Sharp FU40SE - fault finding circuit diagram, working principle and more
How the air purifier works
The air purifier uses the internal fan to intake the air in the room through the intake port and discharges the air through the exhaust port after cleaning the air is passed through the internal filters active carbon filter and dust collection filter (HEPA filter). The unit then repeats this process. Odor ingredients are removed by repeatedly passing them through the deodorization filter for gradual adsorption. (At this time, the dust collection filter also adsorbs odor ingredients.)
The air purifier uses the internal fan to intake the air in the room through the intake port and discharges the air through the exhaust port after cleaning the air is passed through the internal filters active carbon filter and dust collection filter (HEPA filter). The unit then repeats this process. Odor ingredients are removed by repeatedly passing them through the deodorization filter for gradual adsorption. (At this time, the dust collection filter also adsorbs odor ingredients.)
Some
of the odor ingredients absorbed by the filters become separated and are
discharged through the exhaust port as odor. Depending on the usage
environment, this odor may become strong in several months and the exhaust port
may smell. In this case, replace the filters.
While
this product is plugged in, it consumes the stand-by power of approximately
0.8W to activate the electric circuit.
Based
on the standard of The Japan Electrical Manufacturers Association, JEM1467 The
size of the room to be referred to is the one in which dust concentration of
1.25mg/m3 may be reduced to 0.15mg/m 3 within 30 minutes under the condition
that the natural ventilation is performed once per hour.
Based
on the standard of The Japan Electrical Manufacturers Association, JEM1467 Ten
cigarettes are smoked per day in the place where the air cleaner is installed.
Circuit
description
1) Noise-prevention circuit
This circuit protects the circuit from the external noise and lightning surge coming in from the AC plug, and also absorbs the noise outgoing from the AC plug. It consists of the film capacitor C1 and C4, varistor VRS1, current
fuse FUSE1, and line filter L1.
2) Power supply circuit
a) Vm: The commercial power supply (AC220-240V) is put through the current fuse FUSE1 and the thermal fuse, rectified by the diode bridge DB1, and smoothed by the electrolytic capacitor C2. Then it is supplied as the power input for the fan motor and the hybrid IC (HIC1).
(Vm = approx. DC310 - 340V)
b) VL: The hybrid IC (HIC1) is activated by the DC input Vm and the external coil L2, and has two output terminals.
The first output is changed into VL after being smoothed by the electrolytic capacitor C12.
It is used as the power supply for the buzzer drive circuit, fan motor drive circuit, relay RY1, and high voltage unit drive SSR1 (VL = approx. DC15V).
c) VDD: The second output is smoothed by the electrolytic capacitor C11 before used as the power supply for the microcomputer LSI-1, high-voltage unit drive circuit, relay drive circuit, dust/odor sensor circuits, and LED drive circuit (VDD = approx. DC5V).
3) Power supply clock generation circuit
The voltage between the input terminal to DB1 and its output terminal (GND) is divided by the resistor R21, R22 and R23, and input into the digital transistor Q21. Then it is converted into the DC square wave signal that has the same frequency with the AC power supply, and input into the pin 31 on the microcomputer LSI1 via the resistor R25 and the ceramosonic capacitor C22.
The microcomputer LSI-1 considers it as the source signal for time count, and decides the power supply frequency and controls the output time.
When this signal retains " H " or " L " state for over certain period of time, the microcomputer LSI-1 assumes it to be a power failure and stops outputs from the fan motor, high-voltage unit, dust/odor sensors, buzzer, and LED.
4) Reset circuit
If the VDD is lower than specified, " L " is input into the pin 18 of the microcomputer LSI1 to reset LSI-1 using the circuit consisting of the reset IC (IC2), R31 and C32.
When VDD is higher than specified, " H " is input into the same pin, reset command is canceled, and LSI-1 is started.
This circuit protects the circuit from the external noise and lightning surge coming in from the AC plug, and also absorbs the noise outgoing from the AC plug. It consists of the film capacitor C1 and C4, varistor VRS1, current
fuse FUSE1, and line filter L1.
2) Power supply circuit
a) Vm: The commercial power supply (AC220-240V) is put through the current fuse FUSE1 and the thermal fuse, rectified by the diode bridge DB1, and smoothed by the electrolytic capacitor C2. Then it is supplied as the power input for the fan motor and the hybrid IC (HIC1).
(Vm = approx. DC310 - 340V)
b) VL: The hybrid IC (HIC1) is activated by the DC input Vm and the external coil L2, and has two output terminals.
The first output is changed into VL after being smoothed by the electrolytic capacitor C12.
It is used as the power supply for the buzzer drive circuit, fan motor drive circuit, relay RY1, and high voltage unit drive SSR1 (VL = approx. DC15V).
c) VDD: The second output is smoothed by the electrolytic capacitor C11 before used as the power supply for the microcomputer LSI-1, high-voltage unit drive circuit, relay drive circuit, dust/odor sensor circuits, and LED drive circuit (VDD = approx. DC5V).
3) Power supply clock generation circuit
The voltage between the input terminal to DB1 and its output terminal (GND) is divided by the resistor R21, R22 and R23, and input into the digital transistor Q21. Then it is converted into the DC square wave signal that has the same frequency with the AC power supply, and input into the pin 31 on the microcomputer LSI1 via the resistor R25 and the ceramosonic capacitor C22.
The microcomputer LSI-1 considers it as the source signal for time count, and decides the power supply frequency and controls the output time.
When this signal retains " H " or " L " state for over certain period of time, the microcomputer LSI-1 assumes it to be a power failure and stops outputs from the fan motor, high-voltage unit, dust/odor sensors, buzzer, and LED.
4) Reset circuit
If the VDD is lower than specified, " L " is input into the pin 18 of the microcomputer LSI1 to reset LSI-1 using the circuit consisting of the reset IC (IC2), R31 and C32.
When VDD is higher than specified, " H " is input into the same pin, reset command is canceled, and LSI-1 is started.
5)
Clock circuitThis generates the clock signal required for operation of the microcomputer LSI-1. Its frequency is 4MHz which is supplied from the ceramic oscillator CF1.
6) Key input circuit
The key SW1 on the switch PWB K is connected to the resistor R101.
The key status is input into the pin 7 of the microcomputer LSI-1 via the resistor R102 and the ceramosonic capacitor C101.
Key ON : H, Key OFF : L
7) LED drive circuit
Repetitive signal of " H " and " L " output from the pins 3 - 5 of the microcomputer LSI-1 turns on and off the digital transistors Q110 - Q112.
They are turned on one by one at intervals of certain time. When " L " is output from the pins 11 - 16 of the microcomputer LSI1 as they are turned on, the corresponding LED that are connected to them light up.
The LED to display the cluster mode has two colors of super-high-intensity green and blue.
When in the clean mode, " L " is output from the pin 10 of he microcomputer LSI1, Q114 is turned on, and the blue LED lights up. When in the refresh mode, " L " is output from the pin 9, Q113 is turned on, and the green LED lights up.
Control circuit -Block diagram
8) Remote control receive circuit
The infrared signal transmitted from the remote control is received by the reception unit RU1.
When the H/L signal is input into the pin 8 of the microcomputer LSI-1 via the resistor R81 and the ceramosonic capacitor C83, it is determined from which key the signal was transmitted. C81, C82, and C83 absorb or reduce the disturbing lights, noise derived from its own power supply circuit, and external noise.
9) Dust sensor circuit
When the pulse signal, which is the dust sensor drive signal, is output from the pin 35 of the microcomputer LSI-1 (input into the pin 3 of the sensor connector CN-F), the dust sensor is activated and the sensor output signal (pin 2 of the sensor connector CN-F) is input into the pin 30 of the microcomputer (A/D conversion terminal) via R62 and C63.
Principle of dust sensor
Using the pulse signal input from the microcomputer, the infrared LED inside the dust sensor emits light. When the light is reflected by the dust that passes through the sensor, it is detected by the internal photo acceptance unit and smoothed and amplified, and then output from the terminal.
The infrared signal transmitted from the remote control is received by the reception unit RU1.
When the H/L signal is input into the pin 8 of the microcomputer LSI-1 via the resistor R81 and the ceramosonic capacitor C83, it is determined from which key the signal was transmitted. C81, C82, and C83 absorb or reduce the disturbing lights, noise derived from its own power supply circuit, and external noise.
9) Dust sensor circuit
When the pulse signal, which is the dust sensor drive signal, is output from the pin 35 of the microcomputer LSI-1 (input into the pin 3 of the sensor connector CN-F), the dust sensor is activated and the sensor output signal (pin 2 of the sensor connector CN-F) is input into the pin 30 of the microcomputer (A/D conversion terminal) via R62 and C63.
Principle of dust sensor
Using the pulse signal input from the microcomputer, the infrared LED inside the dust sensor emits light. When the light is reflected by the dust that passes through the sensor, it is detected by the internal photo acceptance unit and smoothed and amplified, and then output from the terminal.
Less
dust: less light acceptance
|
less
output (low voltage)
|
More
dust: more light acceptance
|
more
output (high voltage)
|
Control
After turning the power on, the value obtained 20 seconds after starting the first operation (for 30 seconds, the clean sign of three colors for stabilization is lit one by one) is compared to the initial setting reference value of the microcomputer. If it is clean enough, the reference value is revised, and if it is dirtier than the designated level, the clean sign is changed to the sign that indicates the air is contaminated (orange or red, depending on the level), while the reference value remains the same. The value is compared with the reference value in the previous operation and is controlled 20 seconds or more after the operation is started.
The dust sensor is always activated during operation, and air contamination is checked in every four seconds in relative comparison between the average value and the reference value.
The clean sign is displayed, the fan motor is controlled or the cluster mode is switched according to the level of contamination.
After turning the power on, the value obtained 20 seconds after starting the first operation (for 30 seconds, the clean sign of three colors for stabilization is lit one by one) is compared to the initial setting reference value of the microcomputer. If it is clean enough, the reference value is revised, and if it is dirtier than the designated level, the clean sign is changed to the sign that indicates the air is contaminated (orange or red, depending on the level), while the reference value remains the same. The value is compared with the reference value in the previous operation and is controlled 20 seconds or more after the operation is started.
The dust sensor is always activated during operation, and air contamination is checked in every four seconds in relative comparison between the average value and the reference value.
The clean sign is displayed, the fan motor is controlled or the cluster mode is switched according to the level of contamination.
Reference
value: if the current level is cleaner
than the current value è
the reference values is changed to the current value immediately.
If the current
level is dirtier > the value remains the same.
Than the
reference value > the reference value is revised when the level becomes cleaner than that.
The
dust sensor is activated only during the operation.
It is deactivated while the operation is stopped to cut down the standby power consumption.
It is deactivated while the operation is stopped to cut down the standby power consumption.
10) Odor sensor circuit
The pulse signal, which is the odor sensor drive signal, is output from the pin 37 of the microcomputer LSI1, and the odor sensor is pulse-driven on the circuit of Q71, Q72, R73, R74, R76, and C73.
The sensor output signal is input into the pin 27 (A/D conversion terminal) of the microcomputer via R71 and C71.
Principle of odor sensor
The metal oxide semiconductor in this sensor reacts to ammonia, hydrogen, and alcohol, and changes the resistance.
Weak odor : high resistance high voltage
Strong odor : low resistance low voltage
The pulse signal, which is the odor sensor drive signal, is output from the pin 37 of the microcomputer LSI1, and the odor sensor is pulse-driven on the circuit of Q71, Q72, R73, R74, R76, and C73.
The sensor output signal is input into the pin 27 (A/D conversion terminal) of the microcomputer via R71 and C71.
Principle of odor sensor
The metal oxide semiconductor in this sensor reacts to ammonia, hydrogen, and alcohol, and changes the resistance.
Weak odor : high resistance high voltage
Strong odor : low resistance low voltage
Control
After turning the power on, the value obtained 25 seconds after starting the first operation (for 30 seconds, the clean sign of three colors for stabilization is lit one by one) is set as the reference value and the contamination is decided in relative comparison between the values detected at an interval of approximately one second and the reference value.
According to the contamination level, the clean sign is displayed, the fan motor is controlled, or the cluster mode is switched.
Although the odor sensor is always activated during operation, it is deactivated while the operation is stopped to cut down the standby power consumption.
However, if it comes to a complete stop, the reading condition is altered in the next operation. Therefore, it is activated for one minute in every ten minutes to keep the operating conditions.
After turning the power on, the value obtained 25 seconds after starting the first operation (for 30 seconds, the clean sign of three colors for stabilization is lit one by one) is set as the reference value and the contamination is decided in relative comparison between the values detected at an interval of approximately one second and the reference value.
According to the contamination level, the clean sign is displayed, the fan motor is controlled, or the cluster mode is switched.
Although the odor sensor is always activated during operation, it is deactivated while the operation is stopped to cut down the standby power consumption.
However, if it comes to a complete stop, the reading condition is altered in the next operation. Therefore, it is activated for one minute in every ten minutes to keep the operating conditions.
Reference
value: if the current level is cleaner than the reference value the reference
value is changed to the current value immediately.
If the current level is dirtier than the reference value and the contamination level changes (such as suddenly increased odour of cigarette smoke)
If the current level is dirtier than the reference value and the contamination level changes (such as suddenly increased odour of cigarette smoke)
the
reference value remains the same, but the clean sign is changed to indicate the
air is contaminated (orange or red, depending on the level).
the value in the clean condition (green) is adopted as a new reference value.
If the current level is dirtier than the reference value and the contamination level does not change (Natural change only)
the reference value remains the same.
the value in the cleanest condition at eight-minute intervals is adopted as a new reference value.
the value in the clean condition (green) is adopted as a new reference value.
If the current level is dirtier than the reference value and the contamination level does not change (Natural change only)
the reference value remains the same.
the value in the cleanest condition at eight-minute intervals is adopted as a new reference value.
Control circuit diagram and PWB
11) Buzzer drive circuit
The " H / L " signals output from the pin 34 of the microcomputer LSI1 drive the digital transistor Q51 and sound the buzzer BZ1.
The " H / L " signals output from the pin 34 of the microcomputer LSI1 drive the digital transistor Q51 and sound the buzzer BZ1.
12)
Fan motor drive circuit
The fan motor has four input terminals and one output terminal.
Vm (CN-C7 pin) : DC voltage input to be the source of motor rotation. (Vm = approx. DC310-340V) Vm created by the power supply circuit is directly input and is constantly applied.
GND (CN-C5 pin) : Reference of the electric potential. All potentials such as Vm, Vcc, Vs, and PG indicate the potential differences with GND.
Vcc (CN-C3 pin) : DC voltage input terminal to be the power supply for the circuit that is built in the fan motor. During operation, it turns on Q43 and Q44 by outputting the ÉÅHÉÇ signal from the pin 33 of the microcomputer LSI1 of the fan motor, and supplies the potential almost equal to VL to the Vcc terminal (Vcc = approx. DC15V).
The fan motor has four input terminals and one output terminal.
Vm (CN-C7 pin) : DC voltage input to be the source of motor rotation. (Vm = approx. DC310-340V) Vm created by the power supply circuit is directly input and is constantly applied.
GND (CN-C5 pin) : Reference of the electric potential. All potentials such as Vm, Vcc, Vs, and PG indicate the potential differences with GND.
Vcc (CN-C3 pin) : DC voltage input terminal to be the power supply for the circuit that is built in the fan motor. During operation, it turns on Q43 and Q44 by outputting the ÉÅHÉÇ signal from the pin 33 of the microcomputer LSI1 of the fan motor, and supplies the potential almost equal to VL to the Vcc terminal (Vcc = approx. DC15V).
Vs
(CN-C2 pin) : This input terminal controls the revolution speed of the fan
motor (speed instruction signal).
After supplying Vcc during operation, the PWM (x/256EIs) pulse is output from the pin 6 of the microcomputer LSI-1 and smoothed in the circuit consisting of C41, R41-43, Q41 and Q42. Then it goes through R46 and C43 to supply the DC voltage to the Vs terminal.
(Vs = approx. DC0 E ~ 6V)
When speeding up revolution: the pulse width X is widened Vs voltage is increased
When slowing down revolution: the pulse width X is narrowed Vs voltage is decreased
After supplying Vcc during operation, the PWM (x/256EIs) pulse is output from the pin 6 of the microcomputer LSI-1 and smoothed in the circuit consisting of C41, R41-43, Q41 and Q42. Then it goes through R46 and C43 to supply the DC voltage to the Vs terminal.
(Vs = approx. DC0 E ~ 6V)
When speeding up revolution: the pulse width X is widened Vs voltage is increased
When slowing down revolution: the pulse width X is narrowed Vs voltage is decreased
PG
(CN-C1 pin) : Fan motor revolution speed output terminal (feedback signal)
The pulse signal according to the revolution speed is output and it is input into the pin 32 of the microcomputer LSI1 via the circuit consisting of R47, R44, R45, and C42.
The microcomputer recognizes the current revolution speed based on this PG signal, and controls the Vs signal above to keep the speed to the designated level.
The pulse signal according to the revolution speed is output and it is input into the pin 32 of the microcomputer LSI1 via the circuit consisting of R47, R44, R45, and C42.
The microcomputer recognizes the current revolution speed based on this PG signal, and controls the Vs signal above to keep the speed to the designated level.
13) High-voltage unit drive circuit
The high-voltage unit is the power supply unit that supplies the high voltage to generate ion from the cluster electrode, and it can be activated by inputting AC100V into it.
When the solid state relay SSR1 is turned on, the voltage for commercial power supply drops in the resistors R125 and R126 and approximately AC100V is applied to the high-voltage unit.
During operation, it outputs " L/ H " from the pin 25 of the microcomputer LSI-1, turns on and off Q122 and Q123, and controls and drives SSR1.
The high-voltage unit is the power supply unit that supplies the high voltage to generate ion from the cluster electrode, and it can be activated by inputting AC100V into it.
When the solid state relay SSR1 is turned on, the voltage for commercial power supply drops in the resistors R125 and R126 and approximately AC100V is applied to the high-voltage unit.
During operation, it outputs " L/ H " from the pin 25 of the microcomputer LSI-1, turns on and off Q122 and Q123, and controls and drives SSR1.
14) Relay drive circuit
The anode of the diode D126 on the relay PWB is connected to one line of the cluster electrode, and one side of the relay RY1 contact is connected to the AC input of the high-voltage unit, both via the connector CN-J and
harness. Depending on the mode of the cluster, the output signal from the pin 40 of the microcomputer LSI-1 turns on and off Q121 and Q124, which turns on and off RY1, and switches connection.
The anode of the diode D126 on the relay PWB is connected to one line of the cluster electrode, and one side of the relay RY1 contact is connected to the AC input of the high-voltage unit, both via the connector CN-J and
harness. Depending on the mode of the cluster, the output signal from the pin 40 of the microcomputer LSI-1 turns on and off Q121 and Q124, which turns on and off RY1, and switches connection.
In
clean mode : " H " is output from the pin 40 of the microcomputer
LSI-1 and RY1 is turned off.
In cluster automatic operation ............. It enters the clean mode when the clean sign indicates the air is contaminated (orange or red).
In cluster automatic operation ............. It enters the clean mode when the clean sign indicates the air is contaminated (orange or red).
In
refresh mode: It outputs " L " from the pin 40 of the microcomputer
LSI-1, turns onRY1, and bypasses one side of the cluster electrode and one side
of the AC input of the high-voltage unit to direct the flow of electron in one
way, thus generating minus ion in large volume compared to plus ion.
In
cluster automatic operation ............. It enters the refresh mode when the
clean sign indicates the air is clean (green).
15) EEPROM circuit
During operation, data integrated with the operation time of the fan motor (dirtiness of the filter) is read and written into EEPROM (IC1) using the repetitive signals of " H " and " L " that are input and output from the pins 1 and 2 of the microcomputer LSI-1.
During operation, data integrated with the operation time of the fan motor (dirtiness of the filter) is read and written into EEPROM (IC1) using the repetitive signals of " H " and " L " that are input and output from the pins 1 and 2 of the microcomputer LSI-1.
4. Special modes
Some of them are not used during servicing, and are described for reference only.
Test mode
This is to test malfunctions of circuits and used to check them in mass production process.
Setting procedure: Turn the power on while holding down the ON Operation selector/OFF TIMER button, and press the " OFF timer " button on the remote control within five seconds.
A pip sound is heard and the unit starts the test mode.
Some of them are not used during servicing, and are described for reference only.
Test mode
This is to test malfunctions of circuits and used to check them in mass production process.
Setting procedure: Turn the power on while holding down the ON Operation selector/OFF TIMER button, and press the " OFF timer " button on the remote control within five seconds.
A pip sound is heard and the unit starts the test mode.
Test mode
Troubleshooting table
Exploded view
