电子产品世界

Shaping the input current as a square is the best solution for control: it keeps its value (i.e., the transformer and dimmer load current) above the required minimum for the whole cycle of the line voltage.

This control is obtained using components R8 (sense resistor), R7, and C9. R7 and C9 provide the average MOSFET current, which is the same as the average input current; the MAX16834 maintains this value constant throughout each cycle of the input voltage.

Since this solution does not include electrolytic capacitors, the LED current is a rectified sinusoid (without dimmer) or a rectified sinusoid cut for a part of the angle (with dimmer), because energy is not stored between one cycle of the AC voltage and the following (Figure 3).


Figure 3. LED current is a rectified sinusoid, with frequency equal to twice the line voltage frequency.

The MAX16834 features output overvoltage protection (OVP). With OVP, if the LEDs are disconnected or open the driver turns off and the driver is not damaged.

Test results

This reference design board was tested under these conditions:

• Electronic transformer: Lightech LET-60
• Input voltage of the electronic transformer: 120VAC, 60Hz
• Input voltage of the driver circuit: 12VAC, 60Hz modulated at 40kHz
• Output: 4 series LEDs

We measured (without dimmer):

• LED power: 4.2W
• Efficiency: 77%
• Input power factor: 0.943

This design is compatible with these electronic transformers.

Input Voltage	Maker	Model
120VAC	B+L Technologies	FX95100
120VAC	Eaglerise Electric Electronic (Foshan) Co Ltd.	B04558F1
120VAC	Q Tran®, Inc.	QT10-120/12-NTP-RC
120VAC	Hatch	RS1260M-LED
120VAC	Hatch	VS12-60WD
120VAC	Hatch	VS12-75WD
120VAC	Hatch	RS12-60PILB-LED
120VAC	Hatch	RS12-80m
120VAC	Hatch	RS12-15m
120VAC	Hatch	RS12-30m
120VAC	Lightech	LET-60
120VAC	Lightech	LVT-60
110VAC	Nobile	AFM-70KC
120VAC	Progress Lighting®	P8560-31
120VAC	Wang House Technology	WH-801E6A
120VAC	Wang House Technology	WH-601E2CA-2M
220VAC	Hatch	RS12-60-230m
220VAC	Leadman Electronics®	KY-05036S-12
220VAC	Ly SHLY	021-66770066
220VAC	Nobile	EN-35M
230VAC	Nobile	EN-35ST
230VAC	Nobile	EN-60D2
80-270VAC	NVC® Lighting Technology Corporation	NLD-15W/12V
220VAC	OSRAM®	ECO-ET 60/220

In addition, this solution has been tested to work with the following dimmer/electronic transformer combinations.

Input Voltage	Dimmer Maker	Dimmer Model	Electronic Transformer
120V	Lutron® Electronics	Nova NELV-450	Hatch R12-60M-LED
			B + L FX95100
120V	Lutron Electronics	Skylark SELV-300P	B + L FX95100
120V	Lutron Electronics	Diva DVELV-300P	Hatch R12-80M
			B + L FX95100

This solution has been tested to work correctly with the following dimmer/magnetic transformer combinations.

Input Voltage	Dimmer Maker	Dimmer Model	Magnetic Transformer
120V	Lutron Electronics	Nova NLV-600	Q Tran Qt10-120-12-NTP-PC10VA
			Eaglerise B04558F1 40VA
			Schneider Electric® 150VA150SV43A (Square D)
120V	Lutron Electronics	Diva DLV-600P	Q Tran Qt10-120-12-NTP-PC10VA
			Eaglerise B04558F1 40VA
120V	Lutron Electronics	Skylark SLV-600P	Q Tran Qt10-120-12-NTP-PC10VA
120V	Lutron Electronics	Maestro MALV-600	Q Tran Qt10-120-12-NTP-PC10VA
			Schneider Electric 150VA150SV43A (Square D)

Test procedure

• Turn off the 120VAC/230VAC power supply.
• Connect the input of the trailing-edge dimmer (if present) to the power supply.
• Connect the output of the dimmer to the input of the electronic transformer. Alternatively, connect the input of the transformer to the power supply if no dimmer is present.
• Connect the output of the dimmer to the V_IN1 and V_IN2 board inputs.
• Connect the LEDs between LED+ (anode) and LED- (cathode).
• Turn on the power supply.

1 2

关键词： similar retrofit lamps and MR16 driver solution for