MITSUBISHI SEMICONDUCTOR < STANDERD LINEAR IC >
M62281P/FP
GENERAL PURPOSE CURRENT MODE PWM CONTROL IC
(4) CLM TERMINAL
This terminal is for pulse-by-pulse current limiting.
Current limiting circuit is almost the same as that of M51995.
CLM terminal is separate from CURRENT SENSE terminal allowing the noise filter to be optimized
and the high-speed over current protection.
The voltage detected by the current detecting resistor can be directly input as shown in Fig.7-1, if the
detected voltage is about the threshold voltage(200mV(typ.)), but if the voltage is larger than the
threshold, the voltage has to be input divided by resistors as shown in Fig.7-2.
CLM OUT
RNF
CNF
RCS
CLM OUT
RNF1
CNF
RNF2 RCS
Fig.7-1 peripheral circuit of CLM
Fig. 7-2 peripheral circuit of CLM when the
detected voltage is high.
1000pF to 22000pF is recommended for CNF. Be sure to use 100Ω or less for RNF and
RNF1// RNF2 (*)so that the detection sensitivity is not influenced by the current flown out from CLM
terminal.
Non-inductive resistor is recommended for current detecting resistor.
* RNF1//RNF2 = (RNF1 * RNF2)/(RNF1 + RNF2)
(5) CURRENT SENSE TERMINAL
The voltage proportional to the switching current is supplied to this terminal.
Output duty is controlled by comparing this voltage with the output of error amp..
CLM and CURRENT SENSE terminal is separate from each other, so various settings
are available depending upon the application.
CURRENT
SENSE
OUT
RNF
CNF
RCS VCS
Fig.8 peripheral circuit of CURRENT SENSE
RCS is determined by:
VCS = (VEAOUT - 1.3)/3 (V), where VEAOUT represents the voltage of EAOUT terminal.
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