The programmable current limit threshold and full-scale cable compensation voltage are determined by the values of the RSNS, RSET, RILIMIT, and RIMON resistors. Refer to #SLVSDP6-CLCC.
- RSNS is the current sense resistor. The recommended voltage across RSNS under current limit should be approximately 50 mV as a compromise between accuracy and power dissipation. For example, if current limiting is desired for IOUT(MAX) ≥ 3.3 A, then RSNS = 0.05 V / 3.3 A = 0.01515 Ω. Choose a standard value of 15 mΩ.
- RSET determines the input current to the transconductance amplifier
and current mirror. The amplifier balances the voltage to be equal to that
across RSNS. Choose a RSET value to produce an
ISET current between 75–180 µA at the desired
IOUT(MAX). Considering 50 mV across RSET, a value of
300 Ω will provide approximately 166 µA of ISET current to the
amplifier and mirror circuit. Care should be taken to limit the ISET
current below 200 µA to avoid saturating the internal amplifier circuit.
- RILIMIT in conjunction with the 0.5 × ISET current
produces a voltage on the ILIMIT pin which is proportional to the load current
flowing in RSNS. For details on setting the current limit, see
Current Limit Setting using RILIMIT.
- RIMON in conjunction with the 0.5 × ISET current produces
a voltage on the IMON pin which is proportional to the load current flowing in
RSNS. For details on setting the current limit, see Cable Compensation.