Abstract A DC-DC converter includes an inductor having a first terminal connected to a source of DC voltage to be converted. A power transistor is connected to the other terminal of the inductor and controls the passage of current therethrough. A rectifier has an input connected to the inductor and has an output which comprises the output of the converter. A capacitor has a first electrode connected to the output of the rectifier and a second electrode connected to the emitter of the power transistor, the collector of the power transistor being connected to the inductor. A comparator is connected to the power transistor for controlling the operation thereof in accordance with the capacitor voltage so as to produce a desired converter output voltage. The comparator has a first input connected to receive a first reference potential and a second input coupled to the second electrode of the capacitor. The output of the comparator is coupled to the base of the power transistor. A voltage sensing device is coupled between a second reference voltage and (a) the second electrode of the capacitor, (b) the emitter of the power transistor, and (c) the second input of the comparator.
A DC-DC converter comprising: an inductance for connection at one terminal to a source of DC voltage to be converted; switch means connected to another terminal of the inductance for controlling the passage of current through the inductance; a rectifier having an input connected to the other terminal of the inductance and having an output connected to the output of the converter; a capacitance connected to the output of the rectifier to smooth the voltage thereat; control means connected to the switch means for controlling the operation thereof in dependence on the voltage at the capacitance to produce a desired converter output voltage, and voltage sensing means coupled between the capacitor and the control means, characterized in that the capacitance has a first electrode connected to the output of the rectifier and a second electrode connected to a side of the switch means remote from the inductance, said control means comprises a first comparator having a first input connected to a first source of reference potential, a second input connected to the second electrode of the capacitance and an output connected to a control input of the switch means, and said voltage sensing means has a first terminal coupled to the second electrode of the capacitor and to the second input of the comparator and has a second terminal coupled to a second source of reference potential.
Claim 2
Dependent Claim
227 words
A DC-DC converter comprising: an inductance for connection at one terminal to a source of DC voltage to be converted; switch means connected to another terminal of the inductance for controlling the passage of current through the inductance; a rectifier having an input connected to the other terminal of the inductance and having an output connected to the output of the converter; a capacitance connected to the output of the rectifier to smooth the voltage thereat; control means connected to the switch means for controlling the operation thereof in dependence on the voltage at the capacitance to produce a desired converter output voltage, and voltage sensing means coupled between the capacitor and the control means, characterized in that the capacitance has a first electrode connected to the output of the rectifier and a second electrode connected to a side of the switch means remote from the inductance, said control means comprises a first comparator having a first input connected to a first source of reference potential, a second input connected to the second electrode of the capacitance and an output connected to a control input of the switch means, and said voltage sensing means has a first terminal coupled to the second electrode of the capacitor and to the second input of the comparator and has a second terminal coupled to a second source of reference potential.
Claim 3
Dependent Claim
65 words
A DC-DC converter according to claim 1 and further comprising error feedback means having an input connected to the first electrode of the capacitance, and an output connected to the second input of the first comparator, the feedback means producing at its output a feedback signal in dependence on an error in the voltage at the first electrode of the capacitance exceeding a predetermined level.
Claim 4
Dependent Claim
128 words
A DC-DC converter according to claim 2 wherein the error feedback means comprises a voltage regulator including: amplifier means having an input connected to the input of the error feedback means and an output connected to the output of the converter; a second comparator having a first input connected to the output of the amplifier means, a second input connected to a second source of reference potential and an output connected to the input of the amplifier means; and a third comparator having a first input connected to the output of the amplifier means, a second input connected to the input of the amplifier means in series with a third source of reference potential and an output which is connected to the second input of the first comparator.
Claim 5
Dependent Claim
36 words
A DC-DC converter according to claim 3 wherein means are provided for inhibiting the third comparator and voltage limiting means are connected between the first electrode of the capacitance and the output of the third comparator.
Claim 6
Dependent Claim
31 words
A DC-DC converter according to claim 3 or 4 wherein a variable voltage divider is connected between the output of the amplifier means and the first input of the second comparator.
Claim 7
Dependent Claim
23 words
A DC-DC converter according to claim 5 wherein means are provided for inhibiting the second comparator so as to disable the voltage regulator.