HA16103FPJ/FPK

Rev.3.00 Jun 15, 2005 page 13 of 18

Precautions

If the IC’s ground potential varies suddenly by several volts due to wiring impedance (see figure 6), a false

RES pulse

may be output. The reason for this is that potentials in the

RES pulse generating circuit change together with the V

GND potential. The reference potential of the comparator in figure 7 and the potential of the external capacitor have

different impedances as seen from the comparator, causing a momentary inversion. The solution is to stabilize the

ground potential. Two ways of stabilizing the IC’s ground line are:

• Separate the IC’s ground line from highcurrent ground lines.

• Increase the capacitance (Co) used to smooth the V

Wiring impedance

HA16103PJ/FPJ

Co

SW2

SW1

V

IGN

Wiring impedance

Relay or other load

Figure 6 Typical Circuit

GND

RES

Vout

Vcont

+

–

Wiring impedance

GND

Vout

Vcont

CC

+

−

Wiring impedance

Figure 7

RES Comparator