Currently, the main types of switches available on the market for electric toothbrushes are as follows:

1、Button Switch: A single button is located on the top of the toothbrush. Pressing this button turns the toothbrush on or off.

2、Keypad Switch: A row of keys is located on the handle of the toothbrush. Pressing the corresponding key turns the toothbrush on or off.

3、Rotary Switch: A rotary dial is located on the bottom of the toothbrush. Rotating the dial turns the toothbrush on or off.

The switch type and location may vary among different brands and models of electric toothbrushes, but the basic operation is similar.

As shown in Figure 1 below, this is a connection diagram for the switch/key interface and the TT0301SB protection chip from JY Electronics. A 4-channel discrete ESD diode array, the TT0301SB, is selected to protect the I2C GPIO interface circuit. When a high voltage is generated from the video signal, the resulting high current can be shunted to ground through the ESD protection chip. The high voltage is then clamped at its clamping voltage (Vc), thereby protecting the downstream circuit from being damaged by the surge voltage and maintaining the stability of the signal transmission.

Figure 1: Application Circuit Diagram for ESD Protection Chip on Switch/Key Interface