M54679FP
Function Explanation
1. Ph inputs make a decision the output function.
Ph*A
Ph*B
Out*A
OFF
H
Out*B
OFF
L
L
L
H
L
L
H
H
L
H
H
OFF
OFF
* : 1 or 2
The outputs shut off under Ph*A and Ph*B High condition at the same time.
2. Output current and terminal of output current setting.
I0
I1
Output current ratio
Current sensing comparators
threshold voltage (Vref=5V)
L
L
100%
70%
30%
0%
500mV
350mV
155mV
H
L
L
H
H
H
3. Equivalent circuit of Vref terminal.
The equivalent circuit of Vref terminal is shown in right circuit.
As Vref terminal needs typical 500µA input current, consider this value when Vref voltage is set.
4. Current sensing comparators.
The current sensing comparators compare the voltage (VRs) of current sensing resistor and threshold voltage (VCH) of
this comparators, then if VRs > VCH, the comparators output change and shut off the output.
Vref
18k
3.5k
0.68k
2k
I0
I1
Rev.1.0, Sep.19.2003, page 6 of 12
RENESAS [ RENESAS TECHNOLOGY CORP ]
