MIC2310_08 Datasheet, PDF (1/34 Pages) Micrel Semiconductor – Single-FET, Constant Power-Limit Hot Swap Controller

MIC2310
Single-FET, Constant Power-Limit Hot
Swap Controller
General Description
The MIC2310 is a single-channel, positive voltage,
constant power-limit hot swap controller designed to
provide for the safe insertion and removal of pc boards into
fixed, rack, and pedestal mid- or back-planes using few
external components. In addition, the MIC2310 employs a
patent-pending, output load power-limiting technique
where the current limit is inversely proportional to the
output load voltage, such that the power product will not
exceed the programmed power limit any longer than the
externally programmed primary overcurrent period. The
MIC2310 is ideally suited to address the power-limiting
and timing requirements per the UL60950 specification for
240-VA applications. The MIC2310 incorporates high-side
controller circuitry for an external N-channel MOSFET for
which the MOSFET drain current rate of change is user-
programmable via an external capacitor. The MIC2310
employs dual-speed, dual-level overcurrent fault
protection. The primary overcurrent detector response time
is programmable via an external current sense resistor and
the secondary overcurrent detector is 2-bit user-
programmable and exhibits a very fast (default) response
to faults to ensure that the system power supplies are
protected against catastrophic load current and short-
circuit faults. Additionally, an analog output (voltage) signal
is provided that is proportional to the steady-state load
current to allow monitoring of the system’s power. A
PWRGD signal is provided to indicate a valid output
voltage that can be used to enable a DC-DC power
module.
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
Features
• Provides safe PCB insertion and removal from live
+12V backplanes
• Patent-pending, adaptive circuit breaker threshold
control
– Maintains constant power product at output
– Power-limit product (VA) is externally
programmable for various power applications
• Dual-level, dual-speed overcurrent detection/protection
– Programmable primary detector response time
– Fast (< 1 µs) secondary detector response time to
short circuit conditions
ƒ User-programmable threshold settings via (2)
digital inputs
• Steady-state load current monitoring
• Programmable inrush current slew-rate control
• Electronic circuit breaker functions after fault
– Latch off
– Automatic retry
• Programmable input undervoltage lockout and
overvoltage protection
• Fault reporting:
– Open-drain ‘Power-is-Good’ output
– Open-drain ‘I_FLT’ output signaling for all current
faults
– Shorted R_SENSE and Damaged MOSFET detection
(D-G and D-S shorts)
Applications
• UL60950, EN60950, and CSA1950 systems (240-VA)
• General Power-limiting Applications
• Base stations
• Enterprise servers
• High-reliability servers
• Enterprise switch networks
• +12V backplanes
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
July 2008
M9999-070108-A