3-level bridge driver with single supply and low common mode EMI emission
First Claim
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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, andpausing 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.
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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.
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Citations
15 Claims
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1. A transmission circuit comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system comprising:
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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. - View Dependent Claims (11, 12, 13, 14, 15)
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Specification