What is the electric toothbrush?
An electric toothbrush is a toothbrush that makes rapid automatic bristle motions, either back-and-forth oscillation or rotation-oscillation (where the brush head alternates clockwise and counterclockwise rotation), in order to clean teeth. Motions at sonic speeds or below are made by a motor. In the case of ultrasonic toothbrushes, ultrasonic motions are produced by a piezoelectric crystal. A modern electric toothbrush is usually powered by a rechargeable battery charged through inductive charging when the brush sits in the charging base between uses. Electric toothbrushes can be classified according to the frequency (speed) of their movements as power, sonic or ultrasonic toothbrushes, depending on whether they make movements that are below, in or above the audible range (20–20,000 Hz or 2400–2,400,000 movements per minute), respectively.- Wikipedia
Today, we will provide a solution for wireless electronic toothbrushes,which consist of charging base and power handle.
1 Charging Base As the power input port, it can be divided with the power handle Input ： DC/5.0V
2: Power Handle It is the main part of the toothbrush.
lithium battery 3.7V/600mAh，One button, 3 Gearing white LEDs,2 charging LEDs (Red ON means charging; Green ON indicate full charged )
2-1.settings of the Power handle A． No LED On when Turn off the device； Press the button once to start the machine, the gearing is in the first mode, the white LED1 is on, stop for 0.5 seconds every 30 seconds, remind to change the gearing, if do not press the button during the two minutes, it will automatically stop, and LED1 is off;
B． Press the button twice, the gearing is in the second mode, the LED2 white light is on, stop 0.5 seconds for every 30 seconds, remind the gearing change, if do not press the button during the two minutes, it will automatically stop, and LED2 is off;
C． Press the button 3 times, the gearing is in the Third mode, the LED3 white light is on, stop 0.5 seconds for every 30 seconds, remind the gearing change, if do not press the button during the two minutes, it will automatically stop, and LED3 is off;
D． Press the button 4 times to shut down ·
E ． Press the button at any gearing for 1S to shut down ·
F．This machine is equipped with memory function to automatically save the last used gearing. G．Low power alert: when it comes to 3.3v, the red light on to remind charging is needed; when it comes to 3.0v red light flashing 5 times, then it automatically shutdown.
2-2. Charging function of power handle.
A. When the handle is put into the wireless charging base for charging, the button on the handle does not work; B.When charging, the red LED on the handle flashes, indicating charging; When full, the green LED light is always on, indicating that the battery has been fully charged;
Note: after the gear is fully charged, take the handle out from the charging base, the green light is off, and the device is turned off.
3: Circuit Schematics
3-1 Charging Base
Connect 5V dc to power MCU directly. We use the SN8F5701 to support 5V direct power supply, which can save a step of reducing the voltage of LDO. two PWM of MCU control MOS tube switch, so as to achieve the control of coil L1 frequency, and then generate magnetic field and electromotive force, as the transmitter of wireless charge.
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1) Power and Control:
The end of the power is a coil that can be acted as receiving end of wireless charging for battery. The battery can charge MCU directly. Vdd with AD can realize the function of an electricity monitor. MCU takes charge of the switch function, LED indication, charging function, Motor Control, Power control.
2) Battery Protection;
IC we use XB5351/XB5352, which has all protection functions required for battery application, including overcharge, over-discharge, overcurrent, and load short-circuit protection.
Which can easily get in LCSC
Use 0402/0603，MCU will take charge of it
Use Tact Switch as the media of switching machine and gear control
Use CST118S，dc motor driver, single-channel built-in power MOS full-bridge drive, maximum continuous output current up to 1.8a. It is a common model, the motor can choose an acoustic wave, ultrasonic wave, or other motors.