Patent ID: 8872787
Filing Date: 2014-10-28
Classification: H03K

Abstract:
1. A handheld apparatus, comprising: at least one first touch pad, coupled to a first reference voltage; at least one current-limiting protection unit, coupled between the first reference voltage and the first touch pad, limiting a quantity of current flowing from the first reference voltage through the first touch pad into ground when the first touch pad is short-circuited and is therefore directly grounded; at least one second touch pad; at least one impedance unit, coupled between the second touch pad and a second reference voltage, wherein when an input tool touches the first touch pad and the second touch pad simultaneously, a touch voltage signal is generated on a common contact of the second touch pad and the impedance unit, and a resistance of the impedance unit is greater than a resistance of the input tool; a microprocessor, coupled to the second touch pad, executing a specific function according to the touch voltage signal; and a voltage supply unit, coupled to the microprocessor, generating the first reference voltage and the second reference voltage, and controlled by the microprocessor to turn on the first reference voltage and the second reference voltage periodically when the handheld apparatus is in a power-saving mode or a sleep mode to reduce power consumption of the handheld apparatus.