MP3204 MPS, MP3204 Datasheet - Page 4

• Manufacturer Part Number: MP3204
• Description: 1.3MHz Fixed Frequency 5 White LED Driver
• Manufacturer: MPS

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OPERATION
The MP3204 uses constant frequency, peak
current mode boost regulator architecture to
regulate a series of white LEDs. The operation
of the MP3204 can be understood by referring
to the block diagram of Figure 1. At the start of
each oscillator cycle the FET is turned on
through the control circuitry. To prevent sub-
harmonic oscillations at duty cycles greater
than 50%, a stabilizing ramp is added to the
output of the current sense amplifier and the
result is fed into the positive input of the PWM
comparator. When this voltage equals the
MP3204 Rev. 1.3
9/23/2005
FB
104mV
3
TM
AMPLIFIER
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
+
-
1.3MHz
Figure 1—Functional Block Diagram
OSC
+
© 2005 MPS. All Rights Reserved.
COMPARATOR
www.MonolithicPower.com
+
-
PWM
output voltage of the error amplifier, the power
FET is turned off. The voltage at the output of
the error amplifier is an amplified version of the
difference
voltage and the feedback voltage. This is the
manner in which the peak current level keeps
the output in regulation. If the feedback voltage
begins to drop, the output of the error amplifier
increases. This results in more current flowing
through the power FET, thus increasing the
power delivered to the output.
CONTROL
MP3204 – 6V, 1.3MHz WHITE LED DRIVER
LOGIC
between
AMPLIFIER
CURRENT
SENSE
+
-
the
104mV
M1
MP3204_F01_BD01
1
2
reference
SW
GND
4