Patent ID: 6576885
Filing Date: 2003-06-10
Classification: H03K

Abstract:
A charging/discharging circuit mainly comprising:a first diode having an anode connected to at least one external photodiode and a cathode coupled to an external energy storage element; a first transistor connected to the cathode of the first diode on a first contact thereof, and connected to the external photodiode on a second contact thereof at least one internal photodiode having a cathode connected to a third contact of said first transistor; a second transistor connected the second contact of the first transistor on a first contact thereof, the second transistor having a second contact connected to the third contact of the first transistor; a second diode having a cathode connected to the second contact of the second transistor and an anode connected to a third contact of the second transistor; and, an internal energy-storing element having one end connected to the third contact of the second transistor and another end connected to an anode of the at least one internal photodiode for negatively biasing the third contact of the second transistor during charging of the external energy storage element.