MIC2310
Single-FET, Constant Power-Limit Hot
Swap Controller
Micrel Inc. " 2180 Fortune Drive " San Jose, CA 95131 " USA " tel +1 (408) 944-0800 " fax + 1 (408) 474-1000 " http://www.micrel.com
July 2008
M9999-070108-A
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 systems 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
Micrels 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 祍) secondary detector response time to
short circuit conditions
  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