Single-inductor multiple-output switching converters in PCCM with freewheel switching
AssigneeThe Hong Kong University of Science and Technology
InventorsDongsheng Ma, Wing-Hung Ki, Chi-Ying Tsui
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Abstract
A method and apparatus are disclosed for single-inductor multiple-output switching converter design. With the proposed freewheel switching control, this converter operates in a pseudo-continuous conduction mode (PCCM) and is capable of handling large load currents with a much smaller current ripple and peak inductor current, while retaining low cross regulation. It can also work in discontinuous conduction mode (DCM) for high efficiency at light loads. This design can be applied to have single or multiple outputs and for different types of DC-DC conversions.
Claims15
A circuit for providing a plurality of independently regulated output voltages, said circuit compromising:
- (a) a main switch and an inductive element coupled in series with a source of electric potential;
- (b) a switch coupled in parallel with said inductive element for freewheel switching;
- (c) a first auxiliary switch coupled at a first end to a node between said main switch and said inductive element, and coupled at a second end to produce a first output;
- (d) a second auxiliary switch coupled at a first end to a node between said main switch and said inductive element, and coupled at a second end to produce a second output;
- (e) a switch control coupled to drive the ON and OFF switching of said main switch, said first and second auxiliary switches, and said switch for freewheel switching;
- said switch control gating the main switch when and only when a switching phase begins, said switching phase being a time period when said inductive element stores the energy, transfers the energy to one of said outputs, and experiences freewheel switching,
- (f) a current sensing circuit to detect the current or voltage signal of said main switch, or said first or second auxiliary switch, or said inductive element, or said first or second output, or any combinations of current and voltage signals of previous said components, and
- (g) a circuit to determine a current level during freewheel switching in each of said switching phases.
A circuit for providing a plurality of independently regulated output voltages, said circuit compromising:
- (a) a main switch and an inductive element coupled in series with a source of electric potential;
- (b) a switch for freewheel switching coupled in parallel with said inductive element;
- (c) at least two auxiliary switches, each coupled at a first end to a node between said main switch and said inductive element, and each coupled at a second end to produce at least two corresponding outputs;
- (e) a switch control coupled to drive the ON and OFF switching of said main switch, said at least two auxiliary switches, and said switch for freewheel switching;
- said switch control gating the main switch when and only when a switching phase begins, said switching phase being a cycle when said inductive element stores the energy, transfers the energy to one of said outputs, and experiences freewheel switching,
- (f) a current sensing circuit to detect the current signal of said main switch, or said first or second auxiliary switch, or said inductive element, or said first or second output, or any combinations of current and voltage signals of previous said components, and
- (g) a circuit to determine a current level for freewheel switching in each of said switching phases.
A circuit for providing a single regulated output voltage, said circuit compromising:
- (a) a main switch and an inductive element coupled in series with a source of electric potential;
- (b) a switch for freewheel switching coupled in parallel with said inductive element;
- (c) an auxiliary switch, coupled at said output to a node between said main switch and said inductive element;
- (e) a switch control coupled to drive the ON and OFF switching of said main switch, said auxiliary switch, and said switch for freewheel switching;
- (f) a current sensing circuit to detect the current or voltage signal of said main switch, or said auxiliary switch, or said inductive element, or said output, or any combinations of current and voltage signals of previous said components, and
- (g) a circuit to determine a current level for freewheel switching in each of switching cycle.
Dependencies are inferred from the claim text.