LED drive circuit, LED lighting device, and backlight

An LED drive circuit including a current source generating a temporally altering current and a first to a fourth smoothing capacitor, the drive circuit driving:

• a first LED circuit, containing one LED or series-connected LEDs, which is connected in parallel with the first smoothing capacitor;
• a second LED circuit, containing one LED or series-connected LEDs, which is connected in parallel with the second smoothing capacitor;
• a third LED circuit, containing one LED or series-connected LEDs, which is connected in parallel with the third smoothing capacitor;
• and a fourth LED circuit, containing one LED or series-connected LEDs, which is connected in parallel with the fourth smoothing capacitor,
• the drive circuit comprising:
• a first current-dividing coil containing two coils coupled at a tap to which the current source is also coupled;
• a second current-dividing coil containing two coils coupled at a tap to which an end of the first current-dividing coil is also coupled;
• a third current-dividing coil containing two coils coupled at a tap to which another end of the first current-dividing coil is also coupled;
• a first reverse current blocking diode connected between an end of the second current-dividing coil and an electrode of the first smoothing capacitor;
• a second reverse current blocking diode connected between another end of the second current-dividing coil and an electrode of the second smoothing capacitor;
• a third reverse current blocking diode connected between an end of the third current-dividing coil and an electrode of the third smoothing capacitor;
• and
• a fourth reverse current blocking diode connected to another end of the third current-dividing coil and an electrode of the fourth smoothing capacitor.

An LED drive circuit including a current source generating a temporally altering current and a first to a third smoothing capacitor, the drive circuit driving:

• a first LED circuit, containing one LED or series-connected LEDs, which is connected in parallel with the first smoothing capacitor;
• a second LED circuit, containing one LED or series-connected LEDs, which is connected in parallel with the second smoothing capacitor;
• and a third LED circuit, containing one LED or series-connected LEDs, which is connected in parallel with the third smoothing capacitor,
• the drive circuit comprising:
• first current-dividing coil containing two coils coupled at a tap to which the current source is also coupled;
• a second current-dividing coil containing two coils coupled at a tap to which an end of the first current-dividing coil is coupled;
• a first reverse current blocking diode connected between an end of the second current-dividing coil and an electrode of the first smoothing capacitor;
• a second reverse current blocking diode connected between another end of the second current-dividing coil and an electrode of the second smoothing capacitor;
• and
• a third reverse current blocking diode connected between another end of the first current-dividing coil and an electrode of the third smoothing capacitor.

An LED lighting device including an LED drive circuit including a current source generating a temporally altering current and a first smoothing capacitor and a second smoothing capacitor, the drive circuit driving:

• a first LED circuit, containing one LED or series-connected LEDs, which is connected in parallel with the first smoothing capacitor;
• and a second LED circuit, containing one LED or series-connected LEDs, which is connected in parallel with the second smoothing capacitor, the drive circuit comprising:
• a current-dividing coil containing two coils coupled at a tap so that the current generated in the current source flows into the tap;
• a first reverse current blocking diode connected between an end of the current-dividing coil and an electrode of the first smoothing capacitor;
• and a second reverse current blocking diode connected between another end of the current-dividing coil and an electrode of the second smoothing capacitor.

A backlight including an LED drive circuit including a current source generating a temporally altering current and a first smoothing capacitor and a second smoothing capacitor, the drive circuit driving:

• a first LED circuit, containing one LED or series-connected LEDs, which is connected in parallel with the first smoothing capacitor;
• and a second LED circuit, containing one LED or series-connected LEDs, which is connected in parallel with the second smoothing capacitor, the drive circuit comprising:
• a current-dividing coil containing two coils coupled at a tap so that the current generated in the current source flows into the tap;
• a first reverse current blocking diode connected between an end of the current-dividing coil and an electrode of the first smoothing capacitor;
• and a second reverse current blocking diode connected between another end of the current-dividing coil and an electrode of the second smoothing capacitor.