3-level bridge driver with single supply and low common mode EMI emission

• US 9,564,948 B2
• Filed: 11/18/2011
• Issued: 02/07/2017
• Est. Priority Date: 11/18/2011
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Mueller, Bardo, Arnold, Siegfried, Kofler, Robert, Maschera, Davide
• Primary Examiner(s): Wang, Quan-Zhen
• Assistant Examiner(s): Burgdorf, Stephen
• Application Number:
  US13/299,915
• Publication Number:
  US 20130129016A1
• Time in Patent Office: 1,908 Days
• Field of Search: 340/10.1, 340/10.51, 375/296
• US Class Current: 1/1
• CPC Class Codes: H03K 17/691 using transformer coupling
• CPC Class Codes: H04B 5/26 using coils
• CPC Class Codes: H04B 5/72 for local intradevice communication
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

In one embodiment, a circuit, having a single supply, is provided to transmit a wireless signal with low common mode electromagnetic interference (EMI) emission. The circuit can achieve common mode attenuations of 40 dB or greater as a result of the symmetric built circuit. Also included is a system that includes a transmission circuit and a receiver circuit, and a method of using such a system.

Claims

1. A transmission circuit comprising:

a resonance circuit, located between power-receiving terminals, wirelessly transmitting an information signal to an external circuit;

a capacitor and a resistor connected together in series between the power-receiving terminals; and

switching circuitry configured and arranged for;

generating different levels of square wave voltage signals by controlling coupling of the resonance circuit to power supply terminals, the different levels of square wave voltage signals including upper-level voltage signals, lower-level voltage signals, and mid-level voltage signals, to provide energy to the resonance circuit and, in turn, causing wireless transmission of the information signal; and

when generating the mid-level voltage signals;

eliminating DC current paths between power-receiving terminals and the power supply terminals,

shorting the power-receiving terminals together thereby directing movement of charge stored in the resonance circuit from one of the power receiving terminals to the other power receiving terminal to generate the mid-level voltage signal, and

pausing during switching to create a break-before-make gap, wherein the capacitor and resistor are in a current path which is connected in parallel with the resonance circuit and which conducts current during the break-before-make gap.

2. The transmission circuit of claim 1, wherein the switching circuitry further includes a feedback loop circuit configured and arranged to stabilize a mid-point potential of the circuit.

3. The transmission circuit of claim 1, wherein the switching circuitry includes at least one switch.

4. The transmission circuit of claim 1, wherein the resonance circuit has an operating frequency between 50 KHz and 150 KHz.

5. The transmission circuit of claim 1, wherein the DC current paths are eliminated prior to shorting the power-receiving terminals together.

6. The transmission circuit of claim 1, further including a proportional-integral-derivative controller (PID controller) circuit configured and arranged to control the switching circuitry.

7. The transmission circuit of claim 1, further including a mixed-signals control circuit configured and arranged to control the switching circuitry.

8. The transmission circuit of claim 1, wherein the shorting the power-receiving terminals together discharges an inductor of the resonance circuit.

9. The transmission circuit of claim 8, wherein in generating the different levels of square wave voltage signals by the switching circuit provides a DC current path from one of the power supply terminals to the inductor of the resonance circuit.

10. A system comprising:

a transmission circuit, configured and arranged for transmitting an information signal, the transmission circuit including;

a transmission resonance circuit including a capacitor and a resistor located between power-receiving terminals, configured and arranged to wirelessly transmit the information signal,

switching circuitry configured and arranged for;

generating three different levels of square wave voltage signals by controlling coupling of the power-receiving terminals to power supply terminals, the three different levels of square wave voltage signals including upper-level, lower-level, and mid-level voltage signals, to provide energy to the transmission resonance circuit and, in turn, causing wireless transmission of the information signal, and when generating the mid-level voltage signals;

eliminating DC current paths from each of the power-receiving terminals to the power supply terminals, and

shorting the power-receiving terminals together and thereby directing movement of charge stored in the resonance circuit from one of the power receiving terminals to the other power receiving terminal to generate the mid-level voltage signals; and

pausing during switching to create a break-before-make gap, wherein the capacitor and resistor are in a current path which is connected in parallel with the resonance circuit and which conducts current during the break-before-make gap

a receiver circuit, configured and arranged to receive the information signal, the receiver circuit including;

a receiver resonance circuit configured and arranged to wirelessly receive the information signal, and

an identification circuit configured and arranged to confirm an authenticity of the transmission circuit.

11. The system of claim 10, wherein the transmission circuit and the receiver resonance circuit are incorporated into an audio amplifier.

12. The system of claim 10, wherein the transmission circuit and the receiver resonance circuit are incorporated into a passive-keyless entry device.

13. The system of claim 11, wherein the transmission circuit and the receiver resonance circuit are incorporated into a contactless charging system.

14. The system of claim 10, wherein the receiver resonator circuitry has an operating frequency between 50 and 150 KHz.

15. The system of claim 10, wherein common mode attenuations of 40 dB or greater are achieved.