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US 10,855,181 B2Granted
PWM/PFM drive scheme for mutually coupled inductive coils
AssigneeApple Inc.
InventorMark Childs
Life of this patent
Estimating the term…
Abstract
A variable efficiency and response buck converter is achieved. The device includes a multi-phase switch, the coupled coils, the filter capacitor, and the load. The multi-phase switch includes the phase control inputs, the circuit common reference, at least two pairs of complementary switches with each switch containing one upper switch and one lower switch, at least two phase control outputs from the complementary switches. The coupled inductive coils are coupled to the phase control outputs to enable weak couplings and strong couplings. Based on the working mode, equivalently the coupled coils can provide strong mutual inductances and weak mutual inductances. The filter capacitors connected to the output of the coupled coils provide high efficiency output to the load.
Claims20
A circuit comprising:
- first and second phase control circuits;
- a switch circuit configured to operate in one of a first mode or a second mode based on switching signals received from the first and second phase control circuits;
- a mutually coupled inductive coil circuit including a first coil coupled to the switch circuit and a second coil configured to operate in accordance with the switching signals, wherein the first and second coils are configured to operate in phase with respect to one another in the first mode, and out of phase with respect to one another in the second mode, wherein operating in the first mode includes performing pulse frequency modulation, and wherein operating in the second mode includes performing pulse width modulation;
- an output node, wherein the first and second coils are coupled to one another at the output node;
- wherein the first and second phase control circuits are configured to tune an inductance of the first and second coils to increase the inductance by operating the first and second coils in-phase when operating in the first mode and reduce the inductance by operating the first and second coils out of phase when operating in the second mode, and further configured to select operation in either the first mode or the second mode depending upon changes to a current demand from of a load circuit coupled to the output node.
2 more elements
A method comprising:
- operating a mutually coupled inductive coil in a first mode in accordance with switching signals provided in a first plurality of states from first and second phase control circuits to a switch circuit, the mutually coupled inductive coil having first and second coils coupled to the switch circuit, wherein operating in the first mode includes the switch circuit causing constructive interference between the first and second coils, wherein operating in the first mode comprises performing pulse frequency modulation and further comprises tuning an inductance of the mutually coupled inductive coil such that the induction is increased;
- operating the mutually coupled inductive coil in a second mode in accordance the switching signals being provided in a second plurality of states, wherein operating in the second mode includes the switch circuit causing destructive interference between the first and second coils, wherein operating in the second mode comprises performing pulse width modulation and further comprises tuning the inductance of the mutually coupled inductive coil such that the induction is decreased;
- and
- determining whether to operate in the first mode or the second mode based on changes to an output voltage present on an output node coupled to the first and second coils.
1 more element
A circuit comprising:
- a first switch pair and a second switch pair;
- first and second phase control circuits configured to generate first and second pluralities of switch control signals, respectively;
- and
- a mutually coupled inductive coil having a first coil and a second coil coupled to the first switch pair and the second switch pair, respectively, wherein the first and second coils are coupled to one another at an output node;
- wherein the first and second phase control circuits are configured to cause the first and second switch pairs to operate in a first mode that comprises:
- performing pulse frequency modulation responsive to a first operating condition on the output node;
- and
- tune an inductance of the first and second coils to increase the inductance by operating the first and second coils in-phase;
- and further configured to cause the first and second switch pairs to operate in a second mode that comprises:
- performing pulse width modulation responsive to a second operating condition on the output node;
- and
- tune the inductance of the first and second coils to decrease the inductance by operating the first and second coils out of phase.
9 more elements
Dependencies are inferred from the claim text.