US Pat. No. 9,942,957

LIGHT EMITTING DIODE DRIVING CIRCUIT

EDISON OPTO (DONGGUAN) CO...

1. A light emitting diode driving circuit, comprising:a power supply for driving a first LED unit and a second LED unit;
a serial-parallel circuit coupled to the first LED unit and the second LED unit and establishing a serial connection for the first LED unit and the second LED unit or a parallel connection for the first LED unit and the second LED unit, the serial-parallel circuit comprising:
a first switch circuit arranged between an output end of the power supply and the first LED unit;
a second switch circuit arranged between the second LED unit and a ground voltage; and
a connecting circuit coupled to the first switch circuit and the second switch circuit; wherein the first LED unit and the second LED unit are in serial connection via the connecting circuit when the first switch circuit and the second switch circuit are off; wherein the first LED unit and the second LED unit are in parallel connection via the connecting circuit when the first switch circuit and the second switch circuit turn on;
a detection unit coupled to the output end of the power supply for generating a corresponding detection signal according to an output voltage of the power supply, the detection unit comprising:
a first voltage-dividing circuit comprising a first end, a second end, and a voltage-dividing end, the first end of the first voltage-dividing circuit coupled to the output end of the power supply, the second end of the first voltage-dividing circuit coupled to the ground voltage, the first voltage-dividing circuit generating a first division voltage at the voltage-dividing end of the first voltage-dividing circuit according to the output voltage of the power supply;
a first transistor switch comprising a first end, a second end, and a third end, wherein the first end of the first transistor switch is coupled to the output end of the power supply and the second end of the first transistor switch is coupled to the voltage-dividing end of the first voltage-dividing circuit; and
a first regulator unit coupled to the first end of the first transistor switch and providing a first regulatory voltage for the first end of the first transistor switch; and
a control unit arranged between the detection unit and the serial-parallel circuit, the control unit determining the first LED unit and the second LED unit to be set up in the serial connection or in the parallel connection according to the corresponding detection signal;
wherein the third end of the first transistor switch is coupled to the control unit and the voltage difference between the first regulatory voltage and the first division voltage turns on or off the first transistor switch and the third end of the first transistor switch generates the corresponding detection signal.

US Pat. No. 9,913,326

LIGHT EMITTING DIODE DRIVING CIRCUIT WITH STABLE DRIVING CURRENT

EDISON OPTO (DONGGUAN) CO...

1. A light emitting diode (LED) driving circuit for at least driving a first LED unit, the first LED unit comprising a first
node and a second node, the first LED unit comprising at least one LED, the LED driving circuit comprising:
a first charging-discharging circuit which is coupled to an alternating-current (AC) current source, wherein the first charging-discharging
circuit comprising;

a first impedance, comprising a first node and a second node;
a first diode, comprising a first node and a second node, wherein the first node of the first diode is coupled to the first
node of the first impedance and the second node of the first diode is coupled to the second node of the first impedance; and

a first energy storing circuit, comprising a first node and a second node, wherein the first node of the first energy storing
circuit is coupled to the second node of the first impedance and the second node of the first diode, and the second node of
the first energy storing circuit is coupled to the second node of the first LED unit; and

at least one first constant-current unit, serially-coupled to a first end of the first charging-discharging circuit, wherein
the first constant-current unit is arranged to regulate current, and the first node of the first LED unit is coupled to the
first constant-current unit;

wherein during a positive half cycle of the AC current source, the first constant-current unit charges the first energy storing
circuit via the first impedance; and during a negative half cycle of the AC current source, the first energy storing circuit
provides discharging current to the first LED unit via the first diode.

US Pat. No. 10,321,526

LIGHT EMITTING DIODE DRIVING CIRCUIT FOR REDUCING FLICKER EFFECT

EDISON OPTO (DONGGUAN) CO...

1. A light emitting diode (LED) driving circuit for driving an LED unit, the LED unit comprising at least one LED, the LED unit having an input node and an output node, the LED driving circuit comprising:a power source, coupled to the input node of the LED unit;
a detection circuit, coupled to the output node of the LED unit, wherein the detection circuit is arranged to generate a detection signal according to an output signal of the LED unit;
a charging-discharging circuit, comprising:
a resistive circuit, having a first node and a second node;
a first diode, having an anode and a cathode, wherein the first diode is coupled to the resistive circuit in parallel; and
an energy storing circuit, having a first node and a second node, wherein the first node of the energy storing circuit is coupled to the second node of the resistive circuit and the anode of the first diode; the second node of the energy storing circuit is coupled to the output node of the LED unit; when a charging path is enabled, the first node of the resistive circuit is coupled to the power source, and the energy storing circuit is charged via the power source, the resistive circuit and the charging path; and when a discharging path is enabled, the cathode of the first diode is coupled to the LED unit, and the energy storing circuit is discharged via the discharging path, the first diode and the LED unit;
a control circuit, coupled to the detection circuit, the charging path and the discharging path, wherein the control circuit is arranged to selectively enable the charging path or enable the discharging path according to the detection signal; and
a third diode, positioned on the discharging path, wherein an anode of the third diode is coupled to the control circuit, and a cathode of the third diode is coupled to the input node of the LED unit.

US Pat. No. 10,694,595

LIGHT EMITTING DIODE DRIVING CIRCUIT WITH LOW HARMONIC DISTORTION

EDISON OPTO (DONGGUAN) CO...

1. A light emitting diode (LED) driving circuit with low harmonic distortion, comprising:a rectifying circuit, for rectifying an alternating current (AC) power source to provide a direct current (DC) voltage output;
a linear constant current circuit, for driving at least an LED;
a current limiting circuit, connected in parallel between the rectifying circuit and the linear constant current circuit, for generating a current limiting effect and determining a current limiting height; and
a current limiting ramp slope determining circuit, connected in parallel between the rectifying circuit and the linear constant current circuit and connected in series with the current limiting circuit, for determining a current limiting ramp slope.