LED CONTROLLING CIRCUIT WITH HIGH POWER FACTOR AND AN LED LIGHTING DEVICE

• US 20140239824A1
• Filed: 08/12/2013
• Published: 08/28/2014
• Est. Priority Date: 08/22/2012
• Status: Active Grant

• Current Assignee: Shenzhen Sunmoon Microelectronics Co., Ltd.
• Original Assignee: Shenzhen Sunmoon Microelectronics Co., Ltd.
• Inventors: Li, Zhaohua
• Granted Patent: US 9,101,014 B2
• Time in Patent Office: Days
• US Class Current: 315/185.R
• CPC Class Codes: H05B 45/395 Linear regulators
• CPC Class Codes: H05B 45/44 with an active control inside an LED matrix
• CPC Class Codes: H05B 45/48 having LEDs organised in strings and incorporating parallel shunting devices
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

The present invention is suitable for an LED controlling field, and provides an LED controlling circuit with high power factor and an LED lighting device. In the present invention, by using an LED current controlling circuit with high power factor comprising a plurality of output current controlling modules, a resistor Re and a reference voltage generating module, the LED groups is driven accordingly in a piecewise manner to be on and a current flows through the LED groups according to the input voltage of the LED strip, without sampling the input voltage of the LED strip by a sampling circuit and without increasing the number of high cost component, which increase the utilization of the LED, the power factor of the whole LED controlling circuit and the efficiency of the system, thereby solving the problem of low power factor and low efficiency system existing in the prior art.

Claims

1. An LED controlling circuit with high power factor, connected with a LED strip which comprises a plurality of LED groups connected in series of which each comprises a number of LEDs connected in series, in parallel or in series-parallel, characterized in that, the LED controlling circuit comprises:

a plurality of output current controlling modules, a resistor Re and a reference voltage generating module;

the number of the plurality of output current controlling modules is equal to the number of the plurality of LED groups, each of the output current controlling modules comprises a current input terminal, a reference voltage terminal and an output terminal, the current input terminal of each output current controlling module is respectively connected to an output terminal of each LED group of the LED groups in a one-to-one manner, an output terminal of each output current controlling module is connected to a first terminal of the resistor Re, a second terminal of the resistor Re is connected to the ground, when the input voltage of the LED strip reaches the sum of a forward conduction voltage of one LED group and all forward conduction voltages of LED groups connected before the one LED group, the output current controlling module connected to the one LED group is correspondingly connected;

the reference voltage generating module comprises a plurality of output terminals, the number of the plurality of output terminals is equal to the number of the plurality of output current controlling modules, the plurality of output terminals are respectively connected to the reference voltage terminal of each output current controlling module in a one-to-one manner, the reference voltage generating module provides a reference voltage to each of the output current controlling modules, the reference voltage and the resistor Re jointly determine the output current of each output current controlling module.

2. The LED controlling circuit of claim 1, characterized in that, the LED controlling circuit further comprises a plurality of resistors, each of the resistors is connected between the output terminals of very two adjacent output current controlling modules of the output current controlling modules, the difference between the number of the resistors and the number of the output current controlling module is 1.

3. The LED controlling circuit of claim 1, characterized in that, the output current controlling module comprises an operational amplifier and an NMOS transistor, a non-inverting input terminal of the operational amplifier is the reference voltage terminal of the output current controlling module, a drain of the NMOS transistor is the current input terminal of the output current controlling module, a gate of the NMOS transistor is connected to an output terminal of the operational amplifier, a substrate of the NMOS transistor is connected the a source of the NMOS transistor, the source of the NMOS transistor and an inverting input terminal are connected together to form the output terminal of the output current controlling module.

4. An LED lighting device, characterized in that, the LED lighting device comprises a rectifier bridge, an LED strip and an LED controlling circuit with high power factor connected with a LED strip which comprises a plurality of LED groups connected in series of which each comprises a number of LEDs connected in series, in parallel or in series-parallel, characterized in that, the LED controlling circuit comprises:

a plurality of output current controlling modules, a resistor Re and a reference voltage generating module;

the number of the plurality of output current controlling modules is equal to the number of the plurality of LED groups, each of the output current controlling modules comprises a current input terminal, a reference voltage terminal and an output terminal, the current input terminal of each output current controlling module is respectively connected to an output terminal of each LED group of the LED groups in a one-to-one manner, an output terminal of each output current controlling module is connected to a first terminal of the resistor Re, a second terminal of the resistor Re is connected to the ground, when the input voltage of the LED strip reaches the sum of a forward conduction voltage of one LED group and all forward conduction voltages of LED groups connected before the one LED group, the output current controlling module connected to the one LED group is correspondingly connected;

the reference voltage generating module comprises a plurality of output terminals, the number of the plurality of output terminals is equal to the number of the plurality of output current controlling modules, the plurality of output terminals are respectively connected to the reference voltage terminal of each output current controlling module in a one-to-one manner, the reference voltage generating module provides a reference voltage to each of the output current controlling modules, the reference voltage and the resistor Re jointly determine the output current of each output current controlling module.

5. The LED controlling circuit of claim 4, characterized in that, the LED controlling circuit further comprises a plurality of resistors, each of the resistors is connected between the output terminals of very two adjacent output current controlling modules of the output current controlling modules, the difference between the number of the resistors and the number of the output current controlling module is 1.

6. The LED controlling circuit of claim 4, characterized in that, the output current controlling module comprises an operational amplifier and an NMOS transistor, a non-inverting input terminal of the operational amplifier is the reference voltage terminal of the output current controlling module, a drain of the NMOS transistor is the current input terminal of the output current controlling module, a gate of the NMOS transistor is connected to an output terminal of the operational amplifier, a substrate of the NMOS transistor is connected the a source of the NMOS transistor, the source of the NMOS transistor and an inverting input terminal are connected together to form the output terminal of the output current controlling module.