Panel driving circuit and ring oscillator clock automatic synchronization method thereof

A ring oscillator clock automatic synchronization method, applied in a panel driving circuit of a panel, the panel driving circuit comprising a master driver and a plurality of slave drivers, the plurality of slave drivers being coupled to the master driver in series respectively, the master driver having a master ring oscillator clock, the ring oscillator clock automatic synchronization method comprising steps of:

• when a vertical blanking interval of a timing happens, the master driver generating a pulse signal to the plurality of slave drivers respectively, wherein a pulse width of the pulse signal equals to N times of the master ring oscillator clock, and N is larger than 0;
• when a slave driver of the plurality of slave drivers receives the pulse signal, the slave driver using a slave ring oscillator clock to count the pulse width of the pulse signal to obtain that the pulse width of the pulse signal equals to M times of the slave ring oscillator clock, wherein M is larger than 0;
• and
• the slave driver comparing M with N to obtain a comparison result and automatically adjusting the slave ring oscillator clock according to the comparison result to make the slave ring oscillator clock achieve synchronization with the master ring oscillator clock.