Patent ID: 7791600
Filing Date: 2010-09-07
Classification: G09G

Abstract:
1. A driving power supply circuit for controlling a driving voltage to have a voltage between a lower reference voltage and a upper reference voltage and for outputting said driving voltage from an output node, comprising; a p-channel MOS transistor connected between a power supply conductor and said output node and being configured to be ON when a first signal has a first logic level and to be OFF when said first signal has a second logic level; a n-channel MOS transistor connected between said output node and a ground conductor and being configured to be OFF when a second signal has the first logic level and to be ON when said second signal has the second logic level; a first comparing circuit configured to compare said driving voltage to said lower reference voltage when said second signal has the first logic level, said first comparing circuit setting said first signal to the second logic level when said driving voltage is higher than said lower reference voltage and setting said first signal to the first logic level when said driving voltage is lower than said lower reference voltage, said first comparing circuit additionally halting the operation thereof and setting said first signal to the second logic level when said second signal has the first logic level; and a second comparing circuit configured to compare said driving voltage to said upper reference voltage when said second signal has the second logic level, said second comparing circuit setting said second signal to the second logic level when said driving voltage is higher than said upper reference voltage and setting said second signal to the first logic level when said driving voltage is lower than said upper reference voltage, said second comparing circuit additionally halting the operation thereof and setting said second signal to the first logic level when said first signal has the first logic level.