Driving circuit of TDA485X and TDA4841PS

As shown in the figure, the driving circuit for TDA485X and TDA484lPS signals is composed of TDA4866. When the positive power supply voltage VP and the retrace power supply voltage VFB are added, the circuit starts to work. The input signal from the I2C bus automatic synchronization offset controller TDA4841PS (or TDA485X) monitored by the PC is input from pins 1 and 2 to the inverting input and non-inverting input of the internal differential input stage. The two internal vertical output stages form a full-bridge current drive output amplifier. After power amplification of the sawtooth wave signal, it is output from pins 6 and 4 to the deflection coil. The sawtooth wave current generates the deflection magnetic field required by the cathode ray tube through the deflection coil to control the electron beam to perform linear scanning. During the retrace period, the retrace generator supplies power to the vertical output stage, so that it has the minimum power consumption in the short retrace time, and at the same time, it is fed back to pin 9 through Rref. In three cases, pin 8 outputs a high-level protection signal: when the temperature is overheated, when the feedback loop works out of range, and during the retrace blanking period. The vertical output stage has temperature protection and coil short circuit protection (pins 4 and 6).