54results about How to "Avoid voltage rise" patented technology

Even when, for example, electric charge is injected into the output transistor due to external factor such as a noise from the outside, to prevent the step-down voltage from rising, the step-down circuit is comprised of an N channel type output transistor which controls the voltage at the control end, a booster, which is connected to the control end of the output transistor and raises the voltage at the control end and a discharge circuit, which discharges the electric charge at the control end of the output transistor so that the power supply voltage inputted from the input end is stepped down to a desired step-down voltage and outputted from the output end.

An open drain driver ( 7 ) selectively switches a MOSFET switch (MN 1 ) which is passively held in the conducting state into the non-conducting state. The MOSFET switch (MN 1 ) switches an AC analogue input signal on a main input terminal ( 3 ) to a main output terminal ( 4 ) and the gate of the MOSFET switch (MN 1 ) is AC coupled by a capacitor (C 1 ) to the drain thereof. The open drain driver ( 7 ) comprises a first MOSFET (MN 2 ) and a second MOSFET (MN 3 ) through which the gate of the MOSFET switch (MN 1 ) is pulled to ground (Vss). The gate of the first MOSFET (MN 2 ) is coupled to the supply voltage (VDD) for maintaining the first MOSFET (MN 2 ) in the open state. A control signal is applied to the gate of the second MOSFET (MN 3 ) for selectively operating the open drain driver ( 7 ) in the conducting state for operating the MOSFET switch (MN 1 ) in the non-conducting state. When the second MOSFET (MN 3 ) is in the non-conducting state, the first MOSFET (MN 2 ) remains in the conducting state until the voltage on a coupling node ( 9 ) between the first and second MOSFETs (MN 2 ,MN 3 ) equals the difference between its gate voltage and its threshold voltage, at which stage, any over-voltages applied to the gate of the MOSFET switch (MN 1 ) are divided between the first and second MOSFETs (MN 2 ,MN 3 ). A coupling diode (D 1 ) coupling the coupling node ( 9 ) to the supply voltage (VDD) clamps the voltage on the coupling node ( 9 ) at the supply voltage (VDD) plus the conducting voltage of the diode (D 1 ), in the event of the voltage on the coupling node ( 9 ) rising after the first MOSFET (MN 2 ) has gone into the non-conducting state. The coupling node ( 9 ) may be capacitively coupled to the supply voltage (VDD) by a coupling capacitor instead of or as well as the diode (D 1 ) for limiting the voltage on the coupling node ( 9 ).

A circuit comprises a control line and a two terminal semiconductor device having first and second terminals. The first terminal is coupled to a signal line, and the second terminal is coupled to the control line. The two terminal semiconductor device is adapted to have a capacitance when a voltage on the first terminal relative to the second terminal is above a threshold voltage and to have a smaller capacitance when a voltage on the first terminal relative to the second terminal is below the threshold voltage. The control line is coupled to a control signal and the signal line is coupled to a signal and is output of the circuit. A signal is placed on the signal line and voltage on the control line is modified (e.g., raised in the case of n-type devices, or lowered for a p-type devices). When the signal falls below the threshold voltage, the two terminal semiconductor device acts as a very small capacitor and the output of the circuit will be a small value. When the signal is above the threshold voltage, the two terminal semiconductor device acts as a large capacitor and the output of the circuit will be influenced by both the value of the signal and the value of the modified voltage on the control line and therefore the signal will be amplified.

The invention relates to a circuit arrangement for providing an operating DC voltage from a mains voltage, more particularly to operating circuits comprising a clocked electronic converter. Such operating circuits are preferably used for lamps or other light sources. The present invention protects such circuit arrangements from transient mains overvoltages. As soon as a mains overvoltage occurs a diverter switch Th connects the voltage-sensitive switch S11 of the electronic converter to a storage capacitor C12.