Setting a stable operating point and EMI control of an H-bridge output stage
AssigneeAnalog Devices International Unlimited Company
InventorsNaoaki Nishimura, Abhishek Bandyopadhyay
Life of this patent
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Abstract
Apparatus and method for establishing a stable operating point of a H-bridge with a center shunt switch. The stable operating point lets a circuit connected to the H-bridge outputs work in a more ideal condition. As such, an H-bridge with a stable operating point will yield a higher performance and/or save power. Since common mode is one of the biggest sources of electromagnetic interference, a stable operating point in an H-bridge also suppresses EMI.
Claims20
A circuit for setting a stable operating point comprising:
- a first half bridge having a first output;
- a second half bridge having a second output;
- a shunt switch in electrical communication with the first and second outputs;
- a common mode voltage source coupled between a first node and a reference node;
- a first resistor coupled in series with a first switch, wherein the first resistor and the first switch are disposed between the first output and the first node;
- and
- a second resistor coupled in series with a second switch, wherein the second resistor and the second switch are disposed between the second output and the first node, and wherein the first switch and the second switch are coupled, via the first node, to the common mode voltage source.
A system for setting a stable operating point in an H-bridge circuit comprising:
- an IDAC;
- a modulator in electrical communication with the IDAC;
- and
- an H-bridge comprising:
- a first half bridge having a first output;
- a second half bridge having a second output;
- a shunt switch in electrical communication with the first and second outputs;
- a common mode voltage source coupled between a first node and a reference node;
- a first resistor coupled in series with a first switch, wherein the first resistor and the first switch are disposed between the first output and the first node;
- and
- a second resistor coupled in series with a second switch, wherein the second resistor and the second switch are disposed between the second output and the first node, and wherein the first switch and the second switch are coupled, via the first node, to the common mode voltage source.
A system for setting a stable operating point comprising:
- an IDAC;
- an integrator coupled to the IDAC configured to receive an IDAC output and a feedback signal;
- a quantizer coupled to the integrator configured to receive and integrator output and generate a quantized signal;
- and
- an H-bridge configured to receive the quantized signal, comprising:
- a first half bridge having a first output;
- a second half bridge having a second output;
- and means for stabilizing an operating point of the H-bridge;
- a common mode voltage source coupled between a first node and a reference node;
- a first resistor coupled in series with a first switch, wherein the first resistor and the first switch are disposed between the first output and the first node;
- and
- a second resistor coupled in series with a second switch, wherein the second resistor and the second switch are disposed between the second output and the first node, and
- wherein the first switch and the second switch are coupled, via the first node, to the common mode voltage source.
Dependencies are inferred from the claim text.