Lcd video conversion circuit

Abstract

Abstract PURPOSE:To eliminate the need of a RAM absorbing the difference of a frame frequency by changing the operating frequency of a circuit generating a video signal for the time of CRT display and the time of LCD display and changing the frame frequency of a video signal by this change of the operating frequency. CONSTITUTION:An MPU 22, a CRTC 23 and a buffer RAM 24 are constituted for the CRT display. The operating clock of the circuit to generate the video signal for a CRT is switched for the time of the CRT display and the time of the LCD display by an operating frequency selection circuit 25. Thus, the difference of the frame frequency which is 50-60Hz at the time of the CRT display and is near 70Hz at the time of the LCD is removed. The video signal in this state is data-changed by a video LCD interface circuit 27 and is displayed on an LCD 28.

Inventors

• 👤 Satoru Tsunekawa
• 👤 Kiyoshige Kinugawa
• 👤 Hiroyuki Mano

Bibliographic Details