| 摘要 |
PROBLEM TO BE SOLVED: To provide a temperature detection circuit for accurately detecting temperature at high sensitivity from a band-gap temperature sensor by using a VCO circuit, and to provide a video device incorporating the temperature detection circuit. SOLUTION: When pn junction is at a temperature T°C, two current values having a predetermined relative ratio can be selected from a pn current source 22 and made to flow, and a clock (TCK) of a frequency corresponding to the voltage value is output from a VOC 3. A frequency detecting circuit 5 calculates the frequency of the TCK by counting the frequency of the TCK with an MCK of high order frequency. Differential voltage of the band-gap temperature sensor 1 is determined by dividing the differential value of the frequency of the TCK corresponding to each current value by a predetermined amplification factor of an amplifier 21, and the temperature T°C is determined referring to a temperature table from the differential voltage. COPYRIGHT: (C)2009,JPO&INPIT |
