KK33197A
Figure 1. Intermittent Wash Wiper Typical Application
This application shows the
KK33197A
with the external wirings and two speed
wiper motor. This application has the Intermittent and Wash Wiper functions.
INTRODUCTION
The
KK33197A
is a wiper timer control device designed for use in harsh automotive applications. The device can perform
the intermittent, after wash, and continuous wiper timer functions. The
KK33197A
is designed to directly drive a wiper
motor relay. The
KK33197A
is suitable for both front and rear wiper applications. The
KK33197A
connects directly to the
vehicle’s battery voltage (Vbat) through a 220Ω
resistor used with a 47
µF
de–coupling filter capacitor. The device has an
internal oscillator controlled by one of two external resistors (R2 and R3) in addition to one external capacitor (C2),
dependent on the application function required. The values of C2 and R2 determine the tb1 time base. Tb1 is used to
generate the relay wiper activation during the INT function (T3) and the after wash timing (T2) during the wash wipe
mode. The values C2 and R3 determine the t
b2
time base. The t
b2
time base is used to generate the pause or intermittent time
(T4). The intermittent wiper function can generate intermittent timing (T4) from less than 500 ms to more than 30 seconds.
The intermittent function of the device can be activated by the INT input connected to either ground or Vbat. The
intermittent timing is externally adjustable by changing the value of resistor R3. The wash wiper timer function detects the
water pump motor’s operation. When the pump motor activation is detected, the
KK33197A
turns the wiper on for the entire
duration of the pump motor’s activation. When the motor is turned off, it generates an after wash timing (T2) to maintain
the wiping action. The W/W pin is connected to the water pump motor through a protection resistor (R4). The
KK33197A
also has a continuous function, which activates the wiper relay whenever the CONT input is activated. The CONT input is
connected to a switch through a protection resistor (R5). The CONT input comparator has an input threshold of Vbb/2 with
hysteresis. The device has internal debounce circuitry, based on the oscillator period. This provides filtering of the
intermittent (INT) and wash wipe (W/W) input signals (see T1 Debounce Timing paragraph that follows). The device
directly drives the wiper motor relay. It internally incorporates a 20 V free wheeling zener diode to protect the device
against overvoltage spikes produced when relay is switched off.
Intermittent Operation
Conditions:
●
W/W not connected or connected to ground.
●
CONT not connected or connected to ground.
●
INT connected to Vbb or to ground.
In this configuration, the circuit will respond to the switching of INT to either Vbb or ground after a time T1
(see T1 Debounce Timing). If INT is disconnected before the end of T1; no action will be taken. After a time T1, the
output will be switched on for a duration, T3 = 16 x 4 x tb1 and then switched off for a duration, T4 = 144 x 4 x tb2.
This sequence will continue to repeat so long as INT is disconnected from Vbb or ground for a time duration greater
than T1. If INT is disconnected during the time T3; the output will remain on for the remainder of T3. This is illustrated
in the diagram on Figure 2.
3
KODENSHI [ KODENSHI KOREA CORP. ]
