MP4001

– UNIVERSAL INPUT HIGH BRIGHTNESS WLED DRIVER

MP4001 Rev 1.02

www.MonolithicPower.com

12

5/1/2018

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© 2018 MPS. All Rights Reserved.

A maximum 110kHz switching frequency is set

by MP4001 to avoid extreme losses in the

circuit and ensure better EMI performance. If

the converter reaches the maximum frequency,

it

will

operate

in

discontinuous

current

conduction mode. Such operation mode should

be avoided since the LED current is out of

regulation.

within the 30kHz to 110kHz range, inductor

design is critical.

bus

out

out

s

LED

bus

(V

V ) V

1

L

f 2 I

V







,

Hiccup Output Short Protection

Due to the minimal on time limitation, the

inductor current will be out of regulation. The

MP4001 can detect such failure and shut down

for about 1.7ms, and then re-tries the operation.

Such hiccup protection can not only eliminate

the thermal issue due to short circuit current,

but also maintain normal operation if the

protection is mis-triggered.

Under-Voltage Lockout (UVLO) Protection

Under-voltage lockout (UVLO) is implemented

to protect the chip from operating at insufficient

supply voltage. The UVLO rising threshold is

about 7.25V while its falling threshold is a

consistent 6.25V.

Thermal Shut down Protection

An

accurate

temperature

protection

is

implemented to prevent the chip from operating

at exceedingly high temperatures. When the

silicon die temperature is higher than its upper

threshold, it shuts down the whole chip. When

the

temperature

is

lower

than

its

lower

threshold,

the

chip

is

enabled

again.