MIC2310 Single-FET, Constant Power-Limit Hot Swap Controller General Description Features The MIC2310 is a single-channel, positive voltage, Provides safe PCB insertion and removal from live constant power-limit hot swap controller designed to +12V backplanes provide for the safe insertion and removal of pc boards into Patent-pending, adaptive circuit breaker threshold fixed, rack, and pedestal mid- or back-planes using few control external components. In addition, the MIC2310 employs a Maintains constant power product at output patent-pending, output load power-limiting technique Power-limit product (VA) is externally where the current limit is inversely proportional to the programmable for various power applications output load voltage, such that the power product will not Dual-level, dual-speed overcurrent detection/protection exceed the programmed power limit any longer than the externally programmed primary overcurrent period. The Programmable primary detector response time MIC2310 is ideally suited to address the power-limiting Fast (< 1 s) secondary detector response time to and timing requirements per the UL60950 specification for short circuit conditions 240-VA applications. The MIC2310 incorporates high-side User-programmable threshold settings via (2) controller circuitry for an external N-channel MOSFET for digital inputs which the MOSFET drain current rate of change is user- Steady-state load current monitoring programmable via an external capacitor. The MIC2310 Programmable inrush current slew-rate control employs dual-speed, dual-level overcurrent fault protection. The primary overcurrent detector response time Electronic circuit breaker functions after fault is programmable via an external current sense resistor and Latch off the secondary overcurrent detector is 2-bit user- Automatic retry programmable and exhibits a very fast (default) response Programmable input undervoltage lockout and to faults to ensure that the system power supplies are overvoltage protection protected against catastrophic load current and short- circuit faults. Additionally, an analog output (voltage) signal Fault reporting: is provided that is proportional to the steady-state load Open-drain Power-is-Good output current to allow monitoring of the systems power. A Open-drain I FLT output signaling for all current PWRGD signal is provided to indicate a valid output faults voltage that can be used to enable a DC-DC power Shorted R and Damaged MOSFET detection SENSE module. (D-G and D-S shorts) Data sheets and support documentation can be found on Micrels web site at www.micrel.com. 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 +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. MIC2310 Typical Application R SENSE Q1 V OUT IRL3713S V IN 2 12V 20A 0.5% D Pak 12 12V C2* 34 R1 R2 C3 C4 C7 0.68F 0.47F 0.01F C1 24 23 22 11 10 21 19 1.5F R3 VCC VCCSENSE SENSE CSLEW CPRIMARY GATE SOURCE 1% 6 18 ENABLE LOADSENSE R9 1 C LOAD UVLO R4 17 GNDSENSE 3 2 1% OVP Q2 MIC2310 16 R5 DISCH ZUMT618 SOT-323 7 S0 1% C DISCH 4 VREG S 1,0 =X,X 8 C6 S1 0.1F VISS CRETRY CPGND AGND HW FLT PWRGD I FLT TO SYSTEM 3 9 2012 1314 15 R8 V MANAGEMENT LOGIC CONTROLLER C5 R7 0.068F R6 Overcurrent Fault Output * The value of C2 is flexible and dependant upon the Power-Good parasitic inductance, which should be minimzed as much Output as possible. A Hardware inductance) for C2 is 56F, minimum Fault Output M9999-070108-A July 2008 2