# US 11,451,130 B2 · Circuit to transfer a signal between different voltage domains and corresponding method to transfer a signal

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- Number: US 11,451,130 B2
- Document ID: US11451130B2
- Status: Granted
- Kind: B2
- Application number: 17/229,554
- Filed: 2021-04-13
- Published: 2021-11-11
- Granted: 2022-09-20
- Earliest claimed: 2020-05-06
- Assignees: STMicroelectronics S.r.l.
- Applicants: STMICROELECTRONICS S.r.l.
- Inventors: Fabrizio Bognanni; Giovanni Caggegi; Giuseppe Cantone; Vincenzo Marano; Francesco Pulvirenti
- Web page: https://patentgrep.com/patent/US11451130B2

## CPC

- H02M 1/08: Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
- H03K 19/018514: {with at least one differential stage (H03K19/018528 and H03K19/018542 take precedence)}
- H02M 3/07: using capacitors charged and discharged alternately by semiconductor devices with control electrode {, e.g. charge pumps}
- H02M 3/158: including plural semiconductor devices as final control devices for a single load
- H03K 17/063: {in field-effect transistor switches}
- H03K 17/6872: {using complementary field-effect transistors}
- H03K 2017/066: {Maximizing the OFF-resistance instead of minimizing the ON-resistance}
- H03K 2217/0063: High side switches, i.e. the higher potential [DC] or life wire [AC] being directly connected to the switch and not via the load
- H03K 2217/0072: Low side switches, i.e. the lower potential [DC] or neutral wire [AC] being directly connected to the switch and not via the load
- H03K 2217/0081: Power supply means, e.g. to the switch driver
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)

## Abstract

A circuit includes a current path and a negative bootstrap circuitry coupled to the current path. The current path is coupled between a floating voltage and a reference ground, and includes a current generator coupled through a resistor to the floating voltage at a first node of the current generator. The current generator is controlled by a pulse signal. The negative bootstrap circuitry includes a pump capacitor coupled to a second node of the current generator and to the reference ground. The pump capacitor is configured to provide a negative voltage at the second node of the current generator based on the pulse signal.

## Claims

### Claim 1

A circuit, comprising:
a first voltage domain of first voltage levels including a first voltage supply and a first voltage reference;
a second voltage domain of second voltage levels including a second voltage supply and a second voltage reference; and
a first circuitry configured to generate a second signal for operation at the second voltage domain based on a control signal, the first circuit including a logic component and a level shifting circuit coupled to the second voltage supply and to the first voltage reference, the level shifting circuit including:
two current paths coupled between the second voltage supply and the first voltage reference;
a negative bootstrap circuit coupled to each of the two current paths; and
a pulse generator coupled to each of the two current paths,
wherein each of the two current paths includes a high voltage transistor coupled through a respective resistor to the second voltage supply and coupled through a respective controlled current generator to the first voltage reference, each of the two current paths is coupled to a respective input of the logic component, the pulse generator is configured to generate pulse signals based on the control signal, the respective controlled current generator is controlled by at least one of the pulse signals generated by the pulse generator, and the negative bootstrap circuit includes at least one pump capacitor coupled to provide a negative voltage at a first node of the respective controlled current generator.

### Claim 2 (depends on 1)

The circuit of claim 1 wherein the logic component is a set reset latch.

### Claim 3 (depends on 1)

The circuit of claim 1 wherein the negative bootstrap circuit includes two pump capacitors each coupled to a respective current generator of the two current paths.

### Claim 4 (depends on 3)

The circuit of claim 3, wherein a first terminal of a pump capacitor of the two pump capacitors is selectively coupled to one of the first voltage reference or the first voltage supply controlled by a pulse signal of the pulse signals generated by the pulse generator.

### Claim 5 (depends on 4)

The circuit of claim 4 comprising a selection circuitry configured to selectively couple the first terminal of the pump capacitor to one of the first voltage reference or the first voltage supply, the selection circuitry including at least one selecting buffer arrangement including a first inverting buffer and a second inverting buffer both coupled to one or more of the pulse signals,
wherein an output of the first inverting buffer is coupled to control a switch coupled between the first node of the respective current generator and the first voltage reference; and
wherein an output of the second inverting buffers is coupled to the first terminal of the pump capacitor, the second inverting buffer controlled by the one or more of the pulse signals to selectively couple the first terminal of the pump capacitor to one of the first voltage supply or the first voltage reference.

### Claim 6 (depends on 5)

The circuit of claim 5 wherein the at least one selecting buffer arrangement includes two selecting buffer arrangements each coupled to one of the two current paths.

### Claim 7 (depends on 1)

The circuit of claim 1 wherein the negative bootstrap circuit includes a single pump capacitor coupled to first nodes of controlled current generators of the two current paths.

### Claim 8 (depends on 7)

The circuit of claim 7 wherein a terminal of the single pump capacitor is selectively coupled to one of the first voltage reference or the first voltage supply controlled by a combination of the pulse signals generated by the pulse generator.

### Claim 9 (depends on 1)

The circuit of claim 1, comprising a floating well device arranged to operate in the second voltage domain.

### Claim 10 (depends on 1)

The circuit of claim 1, comprising a half-bridge switching device arranged to operate in the second voltage domain and including a capacitor for driving a power switch, the capacitor coupled between a bootstrap terminal and an output terminal, the output terminal alternatively switchable between a first DC voltage and a second DC voltage.

### Claim 11

A circuit, comprising:
a pulse generator;
a current path coupled between a first floating voltage and a first reference ground, the current path including a current generator coupled through a resistor to the first floating voltage at a first node of the current generator, and the current generator coupled to be controlled by a pulse signal generated by the pulse generator; and
a negative bootstrap circuitry coupled to the current path, the negative bootstrap circuit including a pump capacitor coupled to a second node of the current generator and to the first reference ground and configured to provide a negative voltage at the second node of the current generator based on the pulse signal generated by the pulse generator,
wherein the current generator is coupled to be controlled by the pulse signal separately from the negative bootstrap circuitry.

### Claim 12 (depends on 11)

The circuit of claim 11 wherein a first terminal of the pump capacitor is selectively coupled to one of the first reference ground or a first voltage supply based on the pulse signal generated by the pulse generator.

### Claim 13 (depends on 11)

The circuit of claim 11 wherein a second terminal of the pump capacitor is coupled to the second node of the current generator.

### Claim 14 (depends on 13)

The circuit of claim 13 wherein the second node of the current generator is coupled to the first reference ground through a first transistor.

### Claim 15 (depends on 14)

The circuit of claim 14 wherein the second terminal of the pump capacitor is coupled to a gate of the first transistor through a first inverting buffer.

### Claim 16 (depends on 15)

The circuit of claim 15 wherein a first voltage supply is coupled to the gate of the first transistor through the first inverting buffer.

### Claim 17 (depends on 16)

The circuit of claim 16 wherein the first inverting buffer is coupled to be controlled by the pulse signal generated by the pulse generator.

### Claim 18

A circuit, comprising:
a current path coupled between a first floating voltage and a first reference ground, the current path including a current generator and a resistor in series; and
a negative bootstrap circuitry coupled to a first node of the current generator, the negative bootstrap circuit including a pump capacitor having a first terminal and a second terminal, the first terminal coupled to the first node of the current generator, the second terminal selectively coupled, through a first inverting buffer, to one of the first reference ground or a first voltage supply,
wherein the current generator is coupled to be controlled by a pulse signal separately from the negative bootstrap circuitry.

### Claim 19 (depends on 18)

The circuit of claim 18 wherein in response to the second terminal of the pump capacitor is coupled to the first voltage supply, the pump capacitor is charged with a potential between the second terminal and the first terminal.

### Claim 20 (depends on 19)

The circuit of claim 19 wherein in response to the second terminal of the pump capacitor is coupled to the first reference ground, the first terminal of the pump capacitor provides a negative voltage at the first node of the current generator based on the potential between the second terminal and the first terminal.