CST118S is widely used in a wireless charging toothbrush solution
Date：August 3, 2014 Views：112741
CST118S is widely used in a wireless charging toothbrush solution
Nowadays, many families are already using electric toothbrushes, and electric toothbrushes are becoming increasingly accepted by consumers. Next, let's introduce electric toothbrushes.
The electric toothbrush makes the brush head vibrate with high frequency through the rapid rotation or vibration of the motor core, instantly decomposes the toothpaste into fine foam, and deeply cleans the gap between teeth. At the same time, the vibration of the brush hair can promote the blood circulation in the mouth and massage the gum tissue.
At present, the market mainly consists of sonic toothbrushes and ultrasonic toothbrushes; According to the power supply method, it can be divided into plug-in power supply and battery driven electric toothbrush.
Now, let's recommend a wireless charging toothbrush solution. This plan consists of two parts: a charging dock and a handle.
1、 Charging dock section 
Nowadays, many families are already using electric toothbrushes, and electric toothbrushes are becoming increasingly accepted by consumers. Next, let's introduce electric toothbrushes.
The electric toothbrush makes the brush head vibrate with high frequency through the rapid rotation or vibration of the motor core, instantly decomposes the toothpaste into fine foam, and deeply cleans the gap between teeth. At the same time, the vibration of the brush hair can promote the blood circulation in the mouth and massage the gum tissue.
At present, the market mainly consists of sonic toothbrushes and ultrasonic toothbrushes; According to the power supply method, it can be divided into plug-in power supply and battery driven electric toothbrush.
Now, let's recommend a wireless charging toothbrush solution. This plan consists of two parts: a charging dock and a handle.
1、 Charging dock section
As a power input terminal, it can be separated from the handle.
Charging power supply: DC/5.0V
Charging power supply: DC/5.0V
2、 Handle section
It is the main part of an electric toothbrush.
Lithium battery 3.7V/600mAh, one button, 3 white LED gears, 2 charging indicator LEDs (red indicates charging; green indicates fully charged)
1. Handle function
A. The handle is turned off and there are no LED lights on the machine;
Press the key once to start the machine. When the gear is in the first mode, the LED1 white light will be on, and the machine will stop for 0.5 seconds every 30 seconds to remind the user to change the position. The machine will stop automatically without pressing the key for two minutes, and the LED1 will go out at the same time;
B. Press the key twice, the gear is in the second mode, the LED 2 white light is on, the machine stops every 30 seconds for 0.5 seconds, reminds the user to change the position, and does not press the key in the middle. The machine automatically shuts down after 2 minutes, and the LED 2 goes out at the same time;
C. Press the key for three times, the gear is in the third mode, the LED 3 white light is on, the machine stops for 0.5 seconds every 30 seconds, the machine shuts down automatically after three minutes without pressing the key in the middle, and the LED 3 is off at the same time;
D. Press the button 4 times to shut down
E. If the key sequence is continuously pressed: shutdown - first gear - second gear - third gear shutdown - first gear Fourth gear -... loop.
F. Press and hold the button for 1 second in any gear to turn off the device
G. This machine has a memory function that automatically saves the last gear used.
H. Low battery prompt: The 3.3V red light is on to indicate charging, and the 3.0V red light flashes 5 times before automatically shutting down
2. Controller charging function
A. When the controller is placed in the wireless charging dock for charging, the buttons on the controller are invalid (i.e. no function);
B. When charging, the red LED on the handle flashes, indicating that it is charging; When fully charged, the green LED light stays on, indicating that the battery is fully charged; Attention: After fully charging the gear, remove the handle from the charging dock. The green light will turn off and the handle will be turned off.
Lithium battery 3.7V/600mAh, one button, 3 white LED gears, 2 charging indicator LEDs (red indicates charging; green indicates fully charged)
1. Handle function
A. The handle is turned off and there are no LED lights on the machine;
Press the key once to start the machine. When the gear is in the first mode, the LED1 white light will be on, and the machine will stop for 0.5 seconds every 30 seconds to remind the user to change the position. The machine will stop automatically without pressing the key for two minutes, and the LED1 will go out at the same time;
B. Press the key twice, the gear is in the second mode, the LED 2 white light is on, the machine stops every 30 seconds for 0.5 seconds, reminds the user to change the position, and does not press the key in the middle. The machine automatically shuts down after 2 minutes, and the LED 2 goes out at the same time;
C. Press the key for three times, the gear is in the third mode, the LED 3 white light is on, the machine stops for 0.5 seconds every 30 seconds, the machine shuts down automatically after three minutes without pressing the key in the middle, and the LED 3 is off at the same time;
D. Press the button 4 times to shut down
E. If the key sequence is continuously pressed: shutdown - first gear - second gear - third gear shutdown - first gear Fourth gear -... loop.
F. Press and hold the button for 1 second in any gear to turn off the device
G. This machine has a memory function that automatically saves the last gear used.
H. Low battery prompt: The 3.3V red light is on to indicate charging, and the 3.0V red light flashes 5 times before automatically shutting down
2. Controller charging function
A. When the controller is placed in the wireless charging dock for charging, the buttons on the controller are invalid (i.e. no function);
B. When charging, the red LED on the handle flashes, indicating that it is charging; When fully charged, the green LED light stays on, indicating that the battery is fully charged; Attention: After fully charging the gear, remove the handle from the charging dock. The green light will turn off and the handle will be turned off.
3、 Principle implementation
1. Charging dock
Connect 5V DC power to directly power up the MCU, using Songhan's SN8F5701, which supports 5V direct power supply and eliminates the need for LDO voltage reduction. Two PWM controlled MOS switches in MCU are used to control the frequency of coil L1, thereby generating a magnetic field and electromotive force as the transmitting end of wireless charging.
Connect 5V DC power to directly power up the MCU, using Songhan's SN8F5701, which supports 5V direct power supply and eliminates the need for LDO voltage reduction. Two PWM controlled MOS switches in MCU are used to control the frequency of coil L1, thereby generating a magnetic field and electromotive force as the transmitting end of wireless charging.
2. Toothbrush handle
1) Power supply and control:
The power end is a coil, which serves as the receiving end for wireless charging and can charge the battery. The battery can directly supply power to the MCU, and VDD comes with AD, which can achieve power monitoring. MCU controls key functions, LED indicators, charging control, motor control, power consumption control, etc., and is the core component of the entire system.
1) Power supply and control:
The power end is a coil, which serves as the receiving end for wireless charging and can charge the battery. The battery can directly supply power to the MCU, and VDD comes with AD, which can achieve power monitoring. MCU controls key functions, LED indicators, charging control, motor control, power consumption control, etc., and is the core component of the entire system.
2) Battery protection:
The IC uses Saixin Micro's XB5351/XB5352, which has all the protection functions required for battery applications (in fact, lithium protection chips can also be MX3510, MX3520C5, MX5320T5, MX3520E8, MX3520P8), including overcharge, overdischarge, overcurrent, and load short circuit protection. Accurate overcharge detection voltage ensures safety and full utilization of charging. During storage, low standby current will consume very little current from the battery.
The IC uses Saixin Micro's XB5351/XB5352, which has all the protection functions required for battery applications (in fact, lithium protection chips can also be MX3510, MX3520C5, MX5320T5, MX3520E8, MX3520P8), including overcharge, overdischarge, overcurrent, and load short circuit protection. Accurate overcharge detection voltage ensures safety and full utilization of charging. During storage, low standby current will consume very little current from the battery.
3) Indicator lights:
The corresponding functional status indicator can be selected as 0402/0603 and controlled by MCU software.
The corresponding functional status indicator can be selected as 0402/0603 and controlled by MCU software.
4) Key switch:
Select a tactile switch as the medium for power on/off and gear control.
Select a tactile switch as the medium for power on/off and gear control.
5) Motor drive:
CST118S is selected, with a single channel DC motor driver and a single channel built-in power MOS full bridge driver. The maximum continuous output current of CST118S can reach 1.8A. CST118S is a commonly used model, and the motor can be selected from sonic, ultrasonic, or other motors.
CST118S is selected, with a single channel DC motor driver and a single channel built-in power MOS full bridge driver. The maximum continuous output current of CST118S can reach 1.8A. CST118S is a commonly used model, and the motor can be selected from sonic, ultrasonic, or other motors.
4、 Design selection
Please choose based on the actual situation. This article provides a reference BOM for self verification.
| Charging dock | Toothbrush handle | Toothbrush handle | ||||||
| Product Name | specifications | number | Product Name | specifications | number | Product Name | specificationsnumber | |
| DC Seat | DC 5V output | 1 | IC | SN8F570213 SOP14 | 1 | capacitance | 100NF 0603 | 2 |
| IC | SN8F5701 SOP8 | 1 | IC | CST118 SOP8 | 1 | capacitance | 10NF 0603 | 3 |
| MOS | P5806NVG SOP8 | 1 | LED | LED write | 4 | resistance | 47K 0603 | 3 |
| capacitance | 100nf 1206 | 1 | LED | LED RED | 1 | resistance | 100K 0603 | 2 |
| capacitance | 10UF 10V 0805 | 1 | LED | LED GREEN | 1 | resistance | 2K 0603 | 1 |
| capacitance | 10PF 0603 | 1 | key | KEY 5.2_5.2_2.0 | 1 | resistance | 3.3R 0402 | 1 |
| resistance | 0R 0603 | 2 | 电池 | 3.7V | 1 | resistance | 100R 0603 | 5 |
| resistance | 51R 0402 | 1 | capacitance | 22NF 1206 | 1 | resistance | 10K 0603 | 2 |
| coil | 2P_6MM | 1 | capacitance | 10UF 0603 | 2 | diode tube | K14 SOD123 | 2 |
| PCB | 1 | Lithium protection | CST3510 SOT23-5 | 1 | transistor | SS8550 | 1 | |
| motor | DC motor | 1 | transistor | SS8050 | 1 | |||
| PCB | 1 | coil | 1 |
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