Intruduction of Series ME-440YYD

High voltage LED constant current source

   Constant source IC can stabilize the current, which is regulated to be constant. This IC is mainly used in series LED power supply. The number of every string red LED can be up to 110 when the input voltage is 220VAC. The input voltage is between 85VAC and 240VAC, and the output current set by the external components is constant. The external circuit is simple, while without inductance or transformer. At the same time, the circuit is small and can be put into the LED lamps and lanterns.

● Input Voltage Range：85V～240V. (AC Input only)

● Output Constant Current Range：10mA～80mA；(Preset by external circuit)

● Operating Temperature Range：-20℃～85℃

●  Precision：±2.5%；±5% ；±10%

●  Efficiency:95% （With resistance load situation）

●  The Number of LEDs in Series： n≤0.9V_inDC/V_F  (n is the number of LEDs in series single circuit ;V_inDC is the voltage of commutate output; V_F is forward voltage drop of each LED).

●  Package：DIP-10

●  Good stability, high performance cost ratio, the usage performance parameter won’t change in large range of working voltage and temperature.

● Good EMC property

Figure 1 Typical Temperature Diagram

●  LED lamps and lanterns

●  Electronic display

●  Industry lighting facility

●  Decorative lighting facility and bulb.

●  LCD Plane display backlight

●  Other LED driver that needn’t be isolated from power supply.

1.In single circuit, ∑VF≤0.9Vin, VF is forward voltage drop of each LED.

2. For the type ME-44002D(20mA) IC, the total voltage of a LED string more than 30V is better. That means the number of LEDs in series need more than 16pcs in a loop (the red LED voltage drop is 1.8V). ME-44004D（40mA）、ME-44006D（60mA）IC are recommended that in series single loop the total voltage drop should be greater than 90V. If there are two or several LED strings merging, each string should be with the same number of LEDs.

3. The best working voltage scope is from 150V to 180V.

Chart1 the Relationship of Current and Resistance

5．Resistance R2: resistance value=0.5*input voltage*1KΩ, (the resistance error scope is 5%). Power value: 1W. For example: when Vin=220V ,R2=110 KΩ. Please make the resistance as far as possible to the IC when designing.

6. R3 is the current compensatory resistance, Recommended value is 10KΩ 1/16W ～ 1/8W resistance 7. C2：Filter capacitance, the recommended values is 1~4.7uF/400V.

8. C1：Smoothing capacitance (100μF/10V)

9. Please pay attention: don’t use Filter Capacitance following the bridge circuit.

10. Give an example to illustrate how to calculate the maximum of the LED number

    Suppose that the input voltage is 220VAC, then VDC=220V*0.9=198V, for every white LED, VF is 3.3V, now the LED quantity is 198V / 3.3V = 60. If the power supply in low voltage, in order to ensure adequate regulation of the chip to drive the LEDs in normal, time the coefficient 0.9 by the above formula again. That is ∑VF= 198V × 0.9 =178V, now the number of white LEDs can be driven up to 54. (This calculation method has considered the range of variation VAC±15%, if the input alternating voltage is stable, the range of variation is not big, the driven LED number will increase.)

11. The first pin is Enable port, effectual when vacant and turn-off when on high level. This pin can not connect with low level. The following circuit diagrams are two modes to enable the IC. Fig 3 is for isolation mode enabling, Fig 4 is for un- isolation mode enabling.

Remark: When using EN pin to control the circuit on or off, add an inductance to limit the current ascender (di/dt). Its value can be 1 to 2.2mH, and the maximum permissible current should be 1.3 times of actual current across the LED load.

 

 Optical coupler closed, IC is on work; while open it the IC inner circuit will disconnect and won’t work.

Fig 3 Isolated mode enabling

 

 

 

EN: Enable port, vacant is effectual; high level is off. This pin is forbidden to connect low level. The transistor V1 recommended type 9301 or 8050, and R4 recommend value is 4.7K or 5.1K when R4 input voltage is 5V.Note: this un-isolation mode enabling can only be used when control-signal and constant source IC is common ground. Fig 4 un-insulated mode enabling

 

Pin definition

Pin	Symbol	Definition	Pin	Symbol	Definition
1	EN	Enable port	2	RS	Start-up resistance
3	OUT-	Negative output	4	BC	compensatory resistance
5	OUT+	Positive output	6	IN+	Positive input
7	NC	No use(forbidden for user)	8	RT	current regulate
9	CP	Smoothing	10	GND	Ground

 

Type Explaintion

 

Remark: Currently we have different types of constant current source IC:

①   ME-44002D，Range of output constant current：10mA～20mA

②   ME-44004D，Range of output constant current：10mA～40mA

③   ME-44006D，Range of output constant current：10mA～60mA