# US 2014/0191681 A1 · Circuitry for current regulated, externally controlled led driving

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2014/0191681 A1
- Document ID: US20140191681A1
- Status: Published application
- Kind: A1
- Application number: 13/735,884
- Filed: 2013-01-07
- Published: 2014-07-10
- Earliest claimed: 2013-01-07
- Assignees: Atmel Corporation
- Inventors: Armin Noller
- Web page: https://patentgrep.com/patent/US20140191681A1

## CPC

- H05B 45/14: using electrical feedback from LEDs or from LED modules
- H03K 3/00: Circuits for generating electric pulses; Monostable, bistable or multistable circuits (H03K4/00 takes precedence; for digital function generators in computers G06F1/02)
- H03K 17/00: Electronic switching or gating, i.e. not by contact-making and –breaking (gated amplifiers H03F3/72; switching arrangements for exchange systems using static devices H04Q3/52)
- H05B 45/397: Current mirror circuits
- H05B 47/10: Controlling the light source
- Y02B 20/30: Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
- 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)
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

A current driver circuit for regulating a light emitting diode (LED) is disclosed. An example driver circuit uses one input node of the driver circuit for controlling both maximum brightness and dimming of an LED coupled to an output node of the driver circuit. The driver circuit supplies a reference voltage (VREF) to its input node. A microcontroller is coupled through a resistor or other resistive component to the input node of the driver circuit and provides the input current, where the input current is adjustable by the resistor value. The driver circuit is configured to drive multiple times the input current from its output node. By adjusting the resistor value the output current of the LED is adjusted. The microcontroller is configured to provide pulse width modulation (PWM). By reducing the duty cycle of the PWM waveform the dimming of the LED can be controlled.

## Claims

### Claim 1

A current driver circuit comprising:
an input node adapted to receive an input current;
an output node adapted to drive an output current;
a solid voltage (SV) module coupled to a reference voltage (VREF) and adapted to receive the VREF, the SV module coupled to the input node and configured to provides the VREF at the input node;
a current receiving (CR) module coupled to the SV module and the input node, the CR module configured to drive the input current from the input node; and
a current mirror (CM) module coupled to the CR module and the output node and configured to receive the input current and drive an output current that is multiple times the input current from the output node.

### Claim 2 (depends on 1)

The circuit of claim 1, wherein the input node is coupled to a first end of a resistor and a driving voltage is coupled to a second end of the resistor, and wherein the input current is a difference of the driving voltage and the VREF divided by a resistor value.

### Claim 3 (depends on 1)

The circuit of claim 1, wherein the circuit is included in an integrated circuit incorporated in a chip.

### Claim 4 (depends on 2)

The circuit of claim 2, wherein the SV module includes an operational amplifier and a non-inverting node of the operational amplifier is coupled to the VREF and an inverting node of the operational amplifier is coupled to the input node, and wherein the operational amplifier is configured to have a voltage of the inverting node the same as VREF.

### Claim 5 (depends on 2)

The circuit of claim 2, wherein the CR module includes a first transistor, wherein the first transistor is configured to drive the input current from the input node.

### Claim 6 (depends on 5)

The circuit of claim 5, wherein the CM module includes a second transistor coupled to the first transistor and coupled back to back a third transistor, wherein the second transistor is configured to receive the input current and the third transistor is configured to drive the output current.

### Claim 7 (depends on 1)

The circuit of claim 1, wherein the output current is between 10 and 1000 times greater than the input current.

### Claim 8 (depends on 1)

The circuit of claim 1, wherein the VREF is a band-gap voltage reference.

### Claim 9 (depends on 2)

The circuit of claim 2, wherein the driving voltage is supplied by a microcontroller configured to incorporate pulse width modulation (PWM), wherein the microcontroller is configured to use PWM to control an average output current of the circuit.

### Claim 10 (depends on 2)

The circuit of claim 2, wherein the resistor value is configured to control the input current and the output current of the circuit.

### Claim 11 (depends on 2)

The circuit of claim 2, wherein the output node is coupled to a light emitting diode (LED).

### Claim 12 (depends on 11)

The circuit of claim 11, wherein the circuit is configured to control a specific LED color and the circuit further includes one or more drivers configured to control one or more LED colors.

### Claim 13

A circuit configured for current regulating of a light emitting diode (LED), the circuit comprising:
a microcontroller configured to generate an output voltage, wherein the output voltage of the microcontroller is configured to incorporate pulse width modulation (PWM);
a current driver including an input node and an output node and configured to receive an input current and to drive an output current, wherein the output current is multiple times the input current, and wherein a reference voltage (VREF) is supplied at the input node of the current driver;
a resistor coupled to the output voltage of the microcontroller from a first end and to the input node of the current driver from a second end, wherein the input current is a difference of the output voltage of the microcontroller and the VREF divided by a resistor value, and wherein the resistor value is configured to adjust the input current and the output current of the current driver; and
an LED coupled to the output node of the current driver, wherein the current driver is configured to drive the output current from the LED, and wherein the resistor value is configured to adjust a maximum current of the LED, and wherein an average current of the LED is adjusted by the PWM.

### Claim 14 (depends on 13)

The circuit of claim 13, wherein the microcontroller is configured to change a duty cycle of the PWM waveform and control a brightness of the LED.

### Claim 15 (depends on 13)

The circuit of claim 13, wherein the output current of the current driver is at least 10 times the input current of the current driver.

### Claim 16 (depends on 13)

The circuit of claim 13, wherein the reference voltage is a band-gap voltage reference.

### Claim 17

A method configured for current regulating of a light emitting diode (LED) by a circuit including a voltage source and a current driver, the method comprising:
generating a reference voltage (VREF) by the current driver, the current driver including an input node and an output node, wherein the input node is coupled to a first end of a resistor;
applying the VREF to the input node of the current driver;
supplying an input voltage by the voltage source to a second end of the resistor;
delivering an input current to the input node of the current driver, wherein the input current is a difference of the input voltage and the VREF divided by a resistor value;
driving an output current from the output node of the current driver coupled to the LED, the output current is multiple times the input current;
controlling a maximum current of the LED by adjusting the resistance value; and
controlling an average current of the LED by incorporating pulse width modulation (PWM) on the input voltage.

### Claim 18 (depends on 17)

The method of claim 17, wherein the output current of the current driver is between 10 and 1000 times the input current of the current driver.

### Claim 19 (depends on 17)

The method of claim 17, wherein the input voltage is supplied by a microcontroller that incorporates PWM, wherein changing a duty cycle of the PWM controls a brightness of the LED.

### Claim 20 (depends on 17)

The method of claim 17, wherein the current driver circuit controls a specific LED color and the circuit further includes one or more current driver circuits for controlling one or more LED colors