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US 2001/0033156 A1Published application
Self-oscillating switch-mode DC to DC conversion with current switching threshold hysteresis
OwnerRobert N. Buonoinventor
Life of this patent
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Abstract
A simple, self-oscillating, DC-to-DC converter current source, using a small number of simple components, with hysteresis around the current switching thresholds. Slight design modifications allow operation in any of several topologies. In another aspect of the invention, operation as a regulated DC-to-DC converter voltage source is achieved through the addition of a small number of additional components, with slight design modifications allowing operation in any of several topologies.
Claims17
A self-oscillating switched mode, DC-to-DC converter for receiving an input voltage and producing an output voltage, comprising:
- a first switch connected between a first input terminal and a first output terminal through a current sensing element, the first input terminal being connected to an input voltage, the first output terminal producing an output voltage, the first switch being either in an OFF or an ON state and when in its ON state conducting an essentially constant current;
- a second switch connected between the first input terminal and the first output terminal, the second switch alternating between a fully ON and a fully OFF state, the second switch having a turn-on threshold depending on a voltage drop between the first switch and the second switch, the state of the second switch depending on the voltage drop between the first switch and the second switch with respect to the turn-on threshold, the second switch operating opposite in phase to the first switch;
- a third switch connected between the first input terminal and the first output terminal, the third switch operating opposite in phase to the second switch, having a state controlled by the second switch;
- a fourth switch connected between the first input terminal and the first output terminal, the fourth switch operating in phase with the third switch, having a state controlled by the third switch;
- a second input terminal connected to a second output terminal, the second input terminal and the second output terminal being further connected to a reference voltage;
- current storage and sensing means receiving current from the fourth switch and producing a voltage drop between the first switch and the second switch, the voltage drop depending on the level of stored current, the voltage drop serving to control the state of the second switch;
- and
- hysteresis means for controlling the turn-on threshold of the second switch.
5 more elements
A self-oscillating switched mode, DC-to-DC converter for receiving an input voltage and producing an output voltage, comprising:
- a first switch connected between a first input terminal and a first output terminal, the first input terminal being connected to an input voltage, the first output terminal being connected to a reference voltage, the first switch being in either an OFF or an ON state and when in its ON state conducting an essentially constant current;
- a second switch connected between the first input terminal and the first output terminal, the second switch alternating between a fully ON and a fully OFF state, the second switch having a turn-on threshold depending on a voltage drop between the first switch and the second switch, the state of the second switch depending on the voltage drop between the first switch and the second switch with respect to the turn-on threshold, the second switch operating opposite in phase to the first switch;
- a third switch connected between the first input terminal and the first output terminal, the third switch operating opposite in phase to the second switch, having a state controlled by the second switch;
- a fourth switch connected between the first input terminal and the first output terminal through a current storage and sensing means, the fourth switch operating in phase with the third switch, having a state controlled by the third switch;
- a second input terminal connected to the first output terminal, the second input terminal and the first output terminal being further connected to a reference voltage;
- a second output terminal separated from the fourth switch by a diode, the second output terminal producing an output voltage in response to current flowing from the current sensing and storage means to the second output terminal through the diode;
- the current storage and sensing means receiving current from the fourth switch and producing a voltage drop between the first switch and the second switch, the voltage drop depending on the level of stored current, the voltage drop serving to control the state of the second switch;
- and
- hysteresis means for controlling the turn-on threshold of the second transistor switch.
6 more elements
A current sensing circuit and switching comparator with hysteresis comprising:
- first, second and third transistors connected in parallel;
- a sense resistor connected between the emitters of the first and second transistors;
- the collector of the first transistor connected to the base of the second transistor and also connected through a resistor to a control input.
A self-oscillating switched mode, isolated, DC-to-DC converter for receiving an input voltage and producing an output voltage, comprising:
- a first switch connected between first and second input terminals through a current sensing element, the first input terminal being connected to an input voltage, the second input terminal being connected to a reference voltage, the first switch remaining in an ON state and conducting an essentially constant current;
- a second switch connected between the first and second input terminals, the second switch alternating between a fully ON and a fully OFF state, the second switch having a turn-on threshold depending on a voltage drop between the first switch and the second switch, the state of the second switch depending on the voltage drop between the first switch and the second switch with respect to the turn-on threshold.
- a third switch connected between the first and second input terminals, the third switch operating opposite in phase to the second switch, having a state controlled by the second switch;
- a fourth switch connected between the first and second input terminals, the fourth switch operating in phase with the third switch, having a state controlled by the third switch;
- current storage and sensing means receiving current from the fourth switch and producing a voltage drop between the first switch and the second switch, the voltage drop depending on the level of stored current, the voltage drop serving to control the state of the second switch;
- hysteresis means for controlling the voltage drop between the first switch and the second switch when the voltage drop is near the turn-on threshold of the second switch to thereby control the turn-on threshold of the second switch;
- and
- a deadtime circuit for maintaining the second switch in the ON state for a fixed time interval after the second switch has switched to the ON state.
5 more elements
Dependencies are inferred from the claim text.