MIC2130 Datasheet, PDF (8/20 Pages) Micrel Semiconductor – High Voltage Synchronous Buck Control IC with Low EMI Option

Micrel, Inc.
Functional Diagram
MIC2130/1
Figure 1. MIC2130/1 Block Diagram
Functional Description
The MIC2130/31 is a voltage mode synchronous buck
controller built for optimum speed and efficiency. It is
designed for wide input voltage range and for high
output power buck converters. Figure 1 shows the block
diagram.
The control loop has two stages of regulation. During
steady-state to medium output disturbances, the loop
operates in fixed frequency, PWM mode while (gm loop),
during a large output voltage disturbance (~±6%
nominal), the loop becomes hysteretic; meaning that for
a short period, the switching MOSFETs are switched on
and off continuously until the output voltage returns to
it’s nominal level. This maximizes transient response for
April 2008
large load steps, while nominally operating in fixed
frequency PWM mode. Voltage mode control is used to
allow for maximum flexibility and maintains good
transient regulation. The operating input voltage range is
8V to 40V and output can be set from 0.7V up to
0.85*V_IN. Start-up surges are prevented using built in
soft start circuitry as well as resistor-less (LSD RDS_ON is
used to sense load current) current sensing for overload
protection. Other protection features include UVLO, over
voltage latch off protection, Power good signal.
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M9999-042108-C