LT6109-1/LT6109-2 BLOCK DIAGRAMS 9 LT6109-2 V+ 100Ω 3k SENSEHI 34V 6V 10 – SENSELO 3k 1 + OUTA 8 V– V– V– V+ 200nA EN/RST 2 ENABLE AND RESET TIMING RESET V+ – INC2 7 OVERCURRENT FLAG OUTC2 3 + V– 400mV V+ REFERENCE + OVERCURRENT FLAG OUTC1 4 – INC1 6 V– 5 610912 F02 Figure 2. LT6109-2 Block Diagram (Comparators with the Same Polarity)APPLICATIONS INFORMATION The LT6109 high side current sense amplifier provides Amplifier Theory of Operation accurate monitoring of currents through an external sense An internal sense amplifier loop forces SENSEHI to have resistor. The input sense voltage is level-shifted from the the same potential as SENSELO as shown in Figure 3. sensed power supply to a ground referenced output and Connecting an external resistor, R is amplified by a user-selected gain to the output. The IN, between SENSEHI and V output voltage is directly proportional to the current flow- SUPPLY forces a potential, VSENSE, across RIN. A corresponding current, I ing through the sense resistor. OUTA, equal to VSENSE/RIN, will flow through RIN. The high impedance inputs of the sense The LT6109 comparators have a threshold set with a built-in amplifier do not load this current, so it will flow through 400mV precision reference and have 10mV of hysteresis. an internal MOSFET to the output pin, OUTA. The open-drain outputs can be easily used to level shift to digital supplies. 610912fa 10 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagrams Applications Information Typical Applications Package Description Revison History Typical Application Related Parts