Low-Side PWM Controller with LED Dimming Capability
• High Speed Current Mode Pulse-Width Modulator
• Easy to Interface with PIC® Microcontroller for
Implementing High-Performance LED Drivers
• Integrated General Purpose Operational Amplifier
that can be Used for Current Sensing
• Internal Oscillator with Adjustable Frequency via
• External Synchronization Option for the Oscillator
• Internal Slope Compensation Circuit
• Current Sense to VEXT Response <120 ns Typical
• Internal Leading Edge Blanking Circuit for Current
• Programmable Current Sense Offset
• Internal Reference Voltage Generator
• Soft Start Capability
• Internal Push-Pull MOSFET Driver with 1A Peak
• Internal MOSFET Driver for Dimming/Load
• Input Voltage Range: 3V to 5.5V
• Undervoltage Lockout Circuit
• Output Overvoltage Protection
• Output Short Circuit Protection
• Overtemperature Protection
• Small 16-Pin QFN 3 x 3 mm Package
• LED Drivers
• Switch Mode Power Supplies
• Brick DC-DC Converters
The MCP1633 High Speed PWM Controller is a pulse-
width modulator developed for standalone power
supply applications. The MCP1633 design is based on
the MCP1632 PWM Controller but includes specific
blocks for PWM LED dimming. It is suitable for use in
topologies requiring a low side MOSFET, such as
Boost, Flyback, SEPIC, CUK, etc.
The MCP1633 uses Current Mode Control to provide
superior bandwidth and transient response, and also
cycle-by-cycle current limiting with adjustable peak
offset. The MCP1633 is also capable of operating in
Voltage Mode Control if required.
The switching frequency of the MCP1633 can be set by
an external resistor between 200 kHz and 2.2 MHz.
The MCP1633 reference voltage is adjustable by using
only one external resistor.
The MCP1633 integrates a current sense amplifier with
programmable gain using external resistors.
The MCP1633 can achieve high performance LED
dimming by “freezing” the compensation network and
load disconnect capability.
The MCP1633 integrates a high speed comparator with
a high performance error amplifier with a PWM latch to
perform the high speed analog Power Supply PWM
Integrated Undervoltage Lockout, Overvoltage
protection and Overtemperature Protection make
designs using the MCP1633 robust over a range of
3 x 3 x 0.9 mm QFN
2020 Microchip Technology Inc.
17 11 VEXT
EP 10 CS
See Table 3-1 for pin information