MP4050 – NON-ISOLATED, HIGH BRIGHTNESS, LED DRIVER

MP4050 Rev.1.02

www.MonolithicPower.com

15

1/18/2016

MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.

© 2016 MPS. All Rights Reserved.

PRO

R2 R3

C1 s

R2 R3







 



Output Power V-I Curve

The thermal performance limits the output

power of MP4050 in very small size LED

application. Different output voltage and output

current specification bring about different

maximum output power delivered form the

MP4050 device.

Figure 9 and Figure 10 separately show the

reference V-I curve in universal input voltage

and high voltage input under following assumed

conditions:

1. Buck topology.

2. Ambient temperature 90 .

℃

3. Around 30kHz working frequency.

4. No PF required where input capacitor >9uF.

5. Not trigger the thermal shutdown and leave

one LED margin.

MP4050 V-I Curve

Universal Input

85VAC~265VAC

100

125

150

175

200

225

250

275

300

325

350

375

400

0 5 1015202530354045505560657075

SOIC8_85VAC

SOIC8_265VAC

TSOT23-5_85VAC

TSOT23-5_265VAC

Figure 9: Universal input V-I curve

(85VAC~265VAC)

MP4050 V-I Curve High

Voltage Input

265VAC

0

50

100

150

200

250

300

350

400

0 20 40 60 80 100120140160180200220

TSOT23-5

SOIC8

Figure 10: High voltage input V-I curve

(200VAC~265VAC)

Power Factor

MP4050 is mainly used for non-isolated, space

constrained and cost sensitive LED driver

solution. As for the PF>0.5 when 120VAC input

required, MP4050 is also the best choose. The

input capacitance is reduced to achieve the

highest possible power factor as PF>0.7 when

120VAC and PF>0.5 when 230VAC if the

output current regulation is not strict.

Surge

Select the appropriate input capacitance to

obtain a good surge performance. With the

input capacitor C2 (4.7uF) and C3 (4.7uF) as

Figure 13, the board can pass 1kV differential

input line 1.2/50us surge test (IEC61000-4-5). It

is recommended to increase the input capacitor

value to suppress above 1kV surge test. As for

high PF required application with lower input

capacitor value giving a greater voltage rise, a

Metal Oxide Varistor (MOV) is typically required

to pass the above 1kV or greater surge test.

Table 1 shows input capacitor value required

for pass the differential surge test.