A novel high voltage power supply is disclosed which generates an unregulated output voltage from a dc input voltage. The magnitude of the unregulated output voltage may exceed the magnitude of the applied dc voltage. This output voltage appears across a capacitor which is in series with an inductor and a switch. The dc voltage is applied across the inductor and switch, and the switch is periodically closed by an oscillator. While the switch is closed, the voltage across the capacitor increases from energy supplied by the dc voltage. When the switch is open, the voltage on the capacitor is further increased by energy that was stored in the inductor while the switch was closed. A sensing circuit controls the opening and closing of the switch. The high voltage power supply is especially adaptable for use with a display of the gas discharge or plasma type.
This invention provides a method and apparatus for determining a precise switching sequence for the power switching elements of electric power delivery systems of the on-off switching type and which enables extremely fast transient response, precise regulation and highly stable operation. The control utilizes the values of the power delivery system power handling network components, a desired output characteristic, a system timing parameter, and the externally imposed operating conditions to determine where steady state operations should be in order to yield desired output characteristics for the given system specifications. The actual state of the power delivery system is continuously monitored and compared to a state-space boundary which is derived from the desired equilibrium condition, and from the information obtained from this comparison, the system is moved to the desired equilibrium condition in one cycle of switching control. Since the controller continuously monitors the power delivery system's externally imposed operating conditions, a change in the conditions is immediately sensed and a new equilibrium condition is determined and achieved, again in a single cycle of switching control.
In a power supply system, an inductance L is connected between a rail at a voltage V.sub.1 and a rail at earth through a switch S. When the switch is opened, a current i.sub.2 flowing from the inductance L is directed to a third rail through a diode D, voltage on the third rail rising to V.sub.2. The system may function as a dc to dc converter with an output voltage between the V.sub.1 rail and V.sub.2 rail equal to V.sub.2 -V.sub.1. The system may alternatively be used in, for example, a reluctance motor drive, in which case a further inductance with associated switch and diode is included in the circuit in inverse configuration to prevent excessive voltage rise on the third rail.
An energy recovery circuit for a plasma display panel charges a panel capacitor using energy within an inductor and recovers the energy from the panel capacitor. The energy recovery circuit supplies the panel capacitor with a clamping voltage enabling a potential of the panel capacitor to be constantly maintained. A controller controls the energy recovery circuit to supply the clamping voltage to the panel capacitor within a period taken to discharge a current of the inductor from a maximum value to a current level greater than zero. The charging timing point of the panel capacitor occurs prior to the current I.sub.L of the inductor L being discharged to zero and/or prior to the panel capacitor Cp being charged up to the sustain potential Vs.
An energy recovery circuit for a plasma display panel charges a panel capacitor using energy within an inductor and recovers the energy from the panel capacitor. The energy recovery circuit supplies the panel capacitor with a clamping voltage enabling a potential of the panel capacitor to be constantly maintained. A controller controls the energy recovery circuit to supply the clamping voltage to the panel capacitor within a period taken to discharge a current of the inductor from a maximum value to a current level greater than zero. The charging timing point of the panel capacitor occurs prior to the current I.sub.L of the inductor L being discharged to zero and/or prior to the panel capacitor Cp being charged up to the sustain potential Vs.
