BA2181 touch step dimming light circuit

The touch-type step dimming lamp made of BA2181 dimming ASIC has the characteristics
of low power consumption,
strong anti-interference ability,
stable operation and
safe use. The
    HA2181
integrated circuit is manufactured by
CMOS Dingyi
and comes in a standard DIP-8
package. The function of each pin
is: Pin
① is the negative
terminal of the power supply. Pin ② is
the touch sensing input terminal. Pin ③ is the keyed remote control signal input terminal, which is not used in this circuit. It passes through the resistor-capacitor element
R. and c4 to ground. Pin ④ is the upper operation mode selection terminal. It has two upper operation modes to choose from.
When it is connected to the negative terminal Vss of the power supply, it is a four-stage step-down dimming; when it is connected to the positive terminal VDD of the power supply, it is Dan, it’s about the mode of operation
. This circuit connects it to ground, the negative terminal of the power supply vs. ． Therefore, when the electrode sheet M is touched repeatedly, four levels of dimming will be performed
. Pin ⑤ is the AC synchronization signal input terminal. Pin ⑥ is the oscillation signal input terminal, and is connected to an external oscillation resistor and capacitor
. Pin ⑦ is the thyristor trigger signal output terminal, which is used to drive the thyristor. Pin ⑧ is the power supply IE terminal.
The BA2181 integrated circuit uses a power supply voltage range of 3-7V, with a typical value of 6V.
    In the figure, the 220V AC power passes through VD]-VD4 to form a bridge rectifier, R. Buck current limit, vs regulated voltage and
C. Filter and output about 6V DC voltage for power consumption of the integrated block. VD5 is an isolation diode, so that
the ⑤ pin of the integrated block can obtain the AC synchronization signal from both ends of VT through the resistor R3 and the voltage divider. ⑦Pin output trigger signal
is added to the gate of the unidirectional thyristor VT through the G coupling station to control its conduction angle. During operation, as long as you repeatedly touch
the electrode sheet M, the brightness of the bulb E will cycle through four gears: slightly bright - brighter - brightest ÷ off -... which is very
convenient. Another feature of this circuit is that the dimmer has only two external leads, which can directly replace ordinary lighting
, transforming ordinary lighting into a four-level step dimmer .