# US 2021/0243864 A1 · Control circuit and control method with fixed bleed time

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- Number: US 2021/0243864 A1
- Document ID: US20210243864A1
- Status: Published application
- Kind: A1
- Application number: 16/652,637
- Filed: 2019-04-28
- Published: 2021-08-05
- Earliest claimed: 2019-04-16
- Assignees: Shenzhen Sunmoon Microelectronics Co., Ltd.
- Applicants: Shenzhen Sunmoon Microelectronics Co., Ltd.
- Inventors: Zhaohua LI
- Web page: https://patentgrep.com/patent/US20210243864A1

## CPC

- H05B 45/3575: by means of dummy loads or bleeder circuits, e.g. for dimmers
- H03K 17/687: the devices being field-effect transistors
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- 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

The present application provides a control circuit and a control method with fixed bleed time, a trigger signal is obtained and transmitted via a detection module; a timing module starts timing upon receiving the trigger signal, and outputs an end-of-timing signal when a preset time is reached; a control module outputs a control signal according to the end-of-timing signal; a bleeder module bleeds off a current within the preset time according to the control signal; and when the control circuit is powered off, the detection module, timing module, control module and bleeder module automatically perform a power-off reset.

## Claims

### Claim 1

A control circuit with fixed bleed time, wherein the control circuit comprising:
a detection module in connection with an output of a rectifier, and configured to obtain and transmit a trigger signal;
a timing module in connection with the detection module, and configured to start timing upon receiving the trigger signal, and to output an end-of-timing signal when a preset time is reached;
a control module in connection with the timing module, and configured to output a control signal according to the end-of-timing signal; and
a bleeder module in connection with the control module, and configured to bleed off a current within the preset time according to the control signal.

### Claim 2 (depends on 1)

The control circuit according to claim 1, wherein the detection module comprises:
a first resistor, a second resistor and a first comparator;
a first end of the first resistor is connected with the output of the rectifier, a second end of the first resistor is connected in common with a first end of the second resistor and a non-inverting input of the first comparator, a second end of the second resistor is grounded, an inverting input of the first comparator is connected with a third reference voltage signal, and an output of the first comparator is connected to the timing module.

### Claim 3 (depends on 1)

The control circuit according to claim 1, wherein the control module is implemented by a latch.

### Claim 4 (depends on 1)

The control circuit according to claim 1, wherein the bleeder module comprises:
a switch, a second switch, a third operational amplifier and a fourth resistor;
a controlled end of the switch is connected with the control module, a first end of the switch is grounded via a sixth resistor and a fifth resistor, a second end of the switch is connected in common with an inverting input of the third operational amplifier, and an output of the second switch, a non-inverting input of the third operational amplifier is connected with a second reference voltage signal, and an output of the third operational amplifier is connected to a controlled end of the second switch, an input of the second switch is connected with a first end of the fourth resistor, and a second end of the fourth resistor is connected with a light emitting diode via a first diode.

### Claim 5 (depends on 4)

The control circuit according to claim 4, wherein the second switch comprises a field effect transistor or a triode;
the drain, gate and source electrode of the field effect transistor are respectively an input end, a controlled end and an output end of the second switch;
the collector, base and emitter electrode of the triode are respectively an input end, a controlled end, and an output end of the second switch.

### Claim 6 (depends on 4)

The control circuit according to claim 4, wherein the switch comprises a field effect transistor or a triode.

### Claim 7

A control method with fixed bleed time the control method comprising:
obtaining, via a detection module, a trigger signal and transmitting the same;
starting, via a timing module, timing upon receiving the trigger signal, and outputting an end-of-timing signal when a preset time is reached;
outputting, via a control module, a control signal according to the end-of-timing signal;
bleeding off, via a bleeder module, a current within the preset time according to the control signal.