Input voltage selecting auxiliary circuit for power converter circuit
Circuits and methods encompassing a power converter that can be started and operated in a reversed unidirectional manner or in a bidirectional manner while providing sufficient voltage for an associated auxiliary circuit and start-up without added external circuitry for a voltage booster and/or a pre-charge circuit—that is, with zero external components or a reduced number of external components. Embodiments include an auxiliary circuit configured to selectively couple the greater of a first or a second voltage from a power converter to provide power to the auxiliary circuit. Embodiments include an auxiliary circuit configured to select a subcircuit coupled to the greater of a first or a second voltage from a power converter to provide an output for the auxiliary circuit. Embodiments include a charge pump including a gate driver configured to be selectively coupled to one of a first voltage node or second voltage node of the charge pump.
1. An auxiliary circuit configured to provide various voltages and/or signals to converter circuit control circuitry and a converter circuit, the converter circuit having a first terminal configured to be selectably coupled to a first voltage and a second terminal configured to be selectably coupled to a second voltage, the auxiliary circuit including at least one input voltage selector configured to be coupled to the first terminal and the second terminal of the converter circuit and to the auxiliary circuit, the at least one input voltage selector configured to (1) selectively couple the greater of the first voltage or the second voltage to provide power to the auxiliary circuit during a startup phase of the auxiliary circuit, and (2) selectively couple the lesser of the first voltage or the second voltage to provide power to the auxiliary circuit during a steady-state operational phase of the auxiliary circuit while the lesser selected voltage meets or exceeds a specified minimum voltage for the steady-state operational phase.
2. The invention of claim 1 , wherein the auxiliary circuit includes one or more subcircuits coupled to a corresponding one input voltage selector.
3. The invention of claim 1 , wherein at least one input voltage selector is an analog multiplexor.
4. The invention of claim 1 , wherein at least one input voltage selector is configured to self-select one of the first voltage or the second voltage to provide power to the auxiliary circuit.
5. The invention of claim 1 , wherein at least one input voltage selector is coupled to a control signal that selects one of the first voltage or the second voltage to provide power to the auxiliary circuit.
6. The invention of claim 1 , wherein at least one input voltage selector includes:
(a) a first input terminal, a second input terminal, and an output terminal;
(b) a first diode coupled in series with a first resistor, the series-coupled first diode and first resistor being coupled in series between the first input terminal and the output terminal; and
(c) a second diode coupled in series with a second resistor, the series-coupled second diode and second resistor being coupled in series between the second input terminal and the output terminal.
7. The invention of claim 1 , wherein at least one input voltage selector includes:
(a) a first input terminal, a second input terminal, and an output terminal;
(b) a first switch coupled in series between the first input terminal and the output terminal; and
(c) a second switch coupled in series between the second input terminal and the output terminal.
8. The invention of claim 1 , wherein at least one input voltage selector includes:
(a) a first input terminal, a second input terminal, and an output terminal;
(b) a first diode coupled in parallel with a first switch, the parallel-coupled first diode and first switch being coupled in series between the first input terminal and the output terminal; and
(c) a second diode coupled in parallel with a second switch, the parallel-coupled second diode and second switch being coupled in series between the second input terminal and the output terminal.
9. The invention of claim 1 , wherein at least one input voltage selector includes:
(a) a first input terminal, a second input terminal, and an output terminal;
(b) a first resistive divider coupled to the first input terminal and having a first central node;
(c) a second resistive divider coupled to the first input terminal and having a second central node;
(d) a comparator having a first input, a second input, and an output coupled to the output terminal;
(e) a first diode coupled between the first central node and the first input of the comparator;
(f) a second diode coupled between the second central node and the first input of the comparator; and
(g) a reference voltage source coupled to the second input of the comparator.
10. The invention of claim 1 , further including at least one gate driver circuit each coupled to a corresponding transistor switch of the converter circuit, each gate driver circuit including a level shifter and gate-drive configured to be selectively coupled to one of a first output source potential or a second output source potential, and to convert an input switch signal having a first level voltage to an output switch signal having a second level voltage, wherein each gate driver circuit is configured to control the corresponding transistor switch of the converter circuit, and the first output source potential comes from a first voltage node of the converter circuit and the second output source potential comes from a second, different voltage node of the converter circuit.
11. A power converter including:
(a) a converter circuit having a first terminal configured to be selectably coupled to a first voltage and a second terminal configured to be selectably coupled to a second voltage;
(b) an auxiliary circuit configured to provide various voltages and/or signals to other circuitry;
(c) at least one input voltage selector coupled to the first terminal and the second terminal of the converter circuit and to the auxiliary circuit, and configured to (1) selectively couple the greater of the first voltage or the second voltage to provide power to the auxiliary circuit during a startup phase of the auxiliary circuit, and (2) selectively couple the lesser of the first voltage or the second voltage to provide power to the auxiliary circuit during a steady-state operational phase of the auxiliary circuit while the lesser selected voltage meets or exceeds a specified minimum voltage for the steady-state operational phase.
12. The invention of claim 11 , wherein the auxiliary circuit includes one or more subcircuits coupled to a corresponding one input voltage selector.
13. The invention of claim 11 , wherein at least one input voltage selector is an analog multiplexor.
14. The invention of claim 11 , wherein at least one input voltage selector is configured to self-select one of the first voltage or the second voltage to provide power to the auxiliary circuit.
15. The invention of claim 11 , wherein at least one input voltage selector is coupled to a control signal that selects one of the first voltage or the second voltage to provide power to the auxiliary circuit.
16. The invention of claim 11 , further including at least one gate driver circuit each coupled to a corresponding transistor switch of the converter circuit, each gate driver circuit including a level shifter and gate-drive configured to be selectively coupled to one of a first output source potential or a second output source potential, and to convert an input switch signal having a first level voltage to an output switch signal having a second level voltage, wherein each gate driver circuit is configured to control the corresponding transistor switch of the converter circuit, and the first output source potential comes from a first voltage node of the converter circuit and the second output source potential comes from a second, different voltage node of the converter circuit.
17. The invention of claim 11 , wherein at least one input voltage selector includes:
(a) a first input terminal, a second input terminal, and an output terminal;
(b) a first diode coupled in series with a first resistor, the series-coupled first diode and first resistor being coupled in series between the first input terminal and the output terminal; and
(c) a second diode coupled in series with a second resistor, the series-coupled second diode and second resistor being coupled in series between the second input terminal and the output terminal.
18. The invention of claim 11 , wherein at least one input voltage selector includes:
(a) a first input terminal, a second input terminal, and an output terminal;
(b) a first switch coupled in series between the first input terminal and the output terminal; and
(c) a second switch coupled in series between the second input terminal and the output terminal.
19. The invention of claim 11 , wherein at least one input voltage selector includes:
(a) a first input terminal, a second input terminal, and an output terminal;
(b) a first diode coupled in parallel with a first switch, the parallel-coupled first diode and first switch being coupled in series between the first input terminal and the output terminal; and
(c) a second diode coupled in parallel with a second switch, the parallel-coupled second diode and second switch being coupled in series between the second input terminal and the output terminal.
20. The invention of claim 11 , wherein at least one input voltage selector includes:
(a) a first input terminal, a second input terminal, and an output terminal;
(b) a first resistive divider coupled to the first input terminal and having a first central node;
(c) a second resistive divider coupled to the first input terminal and having a second central node;
(d) a comparator having a first input, a second input, and an output coupled to the output terminal;
(e) a first diode coupled between the first central node and the first input of the comparator;
(f) a second diode coupled between the second central node and the first input of the comparator; and
(g) a reference voltage source coupled to the second input of the comparator.