Power supply unit
View Patent ↗Embodiments of the invention provide a power supply unit that operates in a standby mode and in a normal mode. The power supply unit comprises a first power supply providing output voltages during the standby mode and a second power supply providing output voltages during the normal mode. A pre-converter provides a stabilized supply voltage for the first and second power supply. The pre-converter operates as an up-converter during the normal operation mode and is switched off during the standby mode together with the second power supply.
1. A projection television including a power supply unit having a standby operation mode and a normal operation mode, comprising:
a first power supply providing a first output voltage during said standby mode;
a second power supply providing a second output voltage during said normal operation mode;
a pre-converter operating as an up-converter during said normal operation mode and being switched-off during said standby mode, said pre-converter providing a first stabilized supply voltage for said first and second power supply;
a coupling means for switching on and off said pre-converter together with said second power supply via a secondary side control voltage;
a digital light processing unit coupled to said first stabilized supply voltage;
a first switch coupled with a control input to said coupling means, said first switch being coupled with a current input to a second supply voltage provided by said first power supply and being coupled with a current output to said second power supply for switching said pre-converter and said second power supply on and off by switching said second supply voltage on and off; and,
a second switch coupled with a control input to a third supply voltage being a DC supply voltage provided by said second power supply for switching through said first stabilized supply voltage to said digital light processing unit, the second switch switching said digital light processing unit on and off together with said pre-converter and said second power supply.
2. The projection television of claim 1 , wherein said first stabilized supply voltage is within a voltage range of 350 to 400 Volts.