LSI/CSI UL ® LS7538-7539 LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747 (516) 271-0400 FAX (516) 271-0405 A3800 TOUCH CONTROL STEP DIMMER LIGHT SWITCH WITH AUTOMATIC GAIN CONTROL (AGC) April 1997 CONNECTION DIAGRAM - TOP VIEW CLOCK 1 V DD(+V ) TOUCH 2 3 LS7538/7539 SYNC LSI FEATURES: • Touch Sensitivity guaranteed to 600pF Touch Plate Capacitance. • Touch Operation independent of line plug polarity. • Pin selection of three available Brightness Step Sequences. • Minimal external components. • AGC Loop stabilizes immediately after Power-Up. • Original brightness maintained during AC Power interruptions less than 0.5 seconds. For longer interruptions circuit will Power-Up in the Off State. • Advanced CMOS design for reliable operating characteristics and low power. • 50/60 Hz Line Frequency. • +6V to +9.5V Operation (VDD-VSS). • 8 Pin Plastic DIP, 8 Pin SOIC 4 8 TRIG 7 V SS ( - V ) 6 MODE 5 CONTROL FIGURE 1 DESCRIPTION: The LS7538/LS7539 are monolithic CMOS Silicon Gate integrated circuits which provide trigger pulses for triac phase control of incandescent lamps. The circuits are designed to operate with a wide variety of lamp sizes ranging from small table lamps to large floor lamps. The AGC Loop automatically adjusts Touch Sensitivity to be independent of lamp size. There are 3 different Brightness Step Sequences for each version of the IC which can be selected by the Three-State MODE pin as shown in Table 1. TABLE 1. BRIGHTNESS STEP MODES MODE PIN BRIGHTNESS STEP SEQUENCE FLOAT OFF-NIGHT LIGHT-MEDIUM-MAXIMUM-OFF VDD OFF-NIGHT LIGHT- LOW MEDIUM-HIGH MEDIUM-MAXIMUM-OFF VSS (LS7538) (LS7539) OFF-MAXIMUM-MEDIUM-NIGHT LIGHT-OFF OFF-MAXIMUM-OFF The lamp brightness is made to vary by changing the delay of the TRIG pulse to the triac from the zero-crossing of the SYNC input. The delays are shown in Table 2 for 50Hz and 60 Hz operation along with Delivered Power as a percentage of Full Power. Figure 2 illustrates the delay. Brightness Night Light Low Medium Medium High Medium Maximum TABLE 2. BRIGHTNESS POWER LEVELS 60Hz Delay (1) 50Hz Delay (2) 6.0 ms 7.2 ms 4.8 ms 5.7 ms 4.0 ms 4.8 ms 3.2 ms 3.8 ms 0.85 ms 1.0 ms % PWR (3) 12 35 53 72 99 (1) With 300KΩ connected between Pin 1 and VDD. (2) With 360KΩ connected between Pin 1 and VDD. (3) Percentage of Full Power delivered to a resistive load by the Triac Switch. .. FIGURE 2. OUTPUT DELAY (Td) SYNC (Pin 2) TRIG(Pin 8) Td Td INPUT/OUTPUT DESCRIPTION: CLOCK Input (Pin 1) An external resistor connected between this input and VDD, along with an internal capacitor and oscillator stage, generates a clock which is used for all timing functions. The recommended value of this resistor for 50Hz and 60Hz operation is specified in the ELECTRICAL CHARACTERISTICS. The resistor value determines the Brightness Levels produced. (See Table 2) SYNC Input (Pin 2) 50 or 60Hz AC input for zero crossing detection. CONTROL I/O (Pin 5) An external R-C network connected between this pin and VDD establishes the controlling feedback for the AGC Loop. MODE Input (Pin 6) A three-state input used to select the desired Brightness Step Sequence (See Table 1). The MODE Input may be changed during operation. VSS (Pin 7) Supply voltage negative terminal. VDD (Pin 3) Supply voltage positive terminal. TOUCH Input (Pin 4) Input for sensing that a touch has been made on a lamp surface or other touch plate. TRIG (Pin 8) The TRIG output produces a negative going pulse every half-cycle of the SYNC input to trigger the triac. The delay, Td, of the pulse with respect to the SYNC signal determines the Brightness Level produced. (See Table 2 & Figure 2) ABSOLUTE MAXIMUM RATINGS: PARAMETER SYMBOL VALUE UNIT DC supply voltage Any input voltage Operating temperature Storage temperature VDD-VSS VIN TA TSTG +11 VSS-0.5 toVDD + 0.5 -20 to +85 -65 to +150 V V °C °C The information included herein is believed to be accurate and reliable. However, LSI Computer Systems, Inc. assumes no responsibilities for inaccuracies, nor for any infringements of patent rights of others which may result from its use. ELECTRICAL CHARACTERISTICS: ( All voltages referenced to Vss. TA = +25˚C unless otherwise specified.) PARAMETER Supply Voltage Supply Current SYMBOL VDD IDD MIN +6 - TYP - MAX +9.5 1.5 UNIT V mA TRIG Sink Current Vo = VDD-3V IO -50 - - mA VDD = +8.0V TRIG Source Current Vo = VDD-0.2V IO +0.1 - - mA VDD = +8.0V TRIG Pulse Width TW - - 90 110 - µsec µsec RC=300KΩ, 60Hz RC=360KΩ, 50Hz TRIG Pulse Delay (Medium Brightness) Td - 4.0 4.8 - msec msec Rc=300KΩ, 60Hz Rc=360KΩ, 50Hz CLOCK Resistor RC - - 300 360 - KΩ KΩ 60Hz 50Hz - - 10 1 - MΩ µF - CL - - 600 pF - CONTROL Resistor Capacitor Touch Plate Capacitance MODE 6 SYNC 2 ZERO-CROSS DETECTOR CLOCK 1 OSCILLATOR TOUCH 4 COUNTER AGC CIRCUIT DECODER STEPPER 5 CONTROL V DD 3 +V V SS 7 -V 7538/39-041197-3 CONDITIONS Output off, VDD = +8.0V FIGURE 3 LS7538/LS7539 BLOCK DIAGRAM OUTPUT DRIVER 8 TRIG FIGURE 4. TOUCH LAMP APPLICATION SCHEMATIC +V R1 LOAD D1 + C1 Z1 AC MAINS - MT2 T1 R5 MT1 G + - C6 -V (SEE NOTE) C5 C2 8 7 TRIG 6 5 V SS MODE CONT LS7538 CLOCK SYNC V DD TOUCH 2 1 R2 D2 R4 TOUCH PLATE (LAMP BODY) 4 3 D3 R3 C3 C4 NOTE: Connect MODE (Pin 6) for desired Brightness Step Sequence (See Table 1) 115VAC APPLICATION R1 R2 R3 (1) R4 R5 C1 C2 C3 = = = = = = = = 20KΩ,1W 470KΩ,1/4W 1KΩ, 1/4W 300KΩ, 1/4W,1% 10MΩ, 1/4W 47µF,16V 1000pF,16V 1000pF,1KV C4 C5 C6 Z1 D1 D2 D3 T1 = = = = = = = = or 1000pF,1KV .03µF,16V 1µF,16V 8.2V,1/4W Zener 1N4004 1N4148 1N4148 Q2004L4 (Typical Triac) Q2004F41(Typical Triac) 220VAC APPLICATION R1 R2 (1) R4 D1 T1 = = = = = or 39KΩ, 2W 910KΩ,1/4W 360KΩ, 1/4W,1% 1N4005 Q4004L4 (Typical Triac) Q4004F41 (Typical Triac) All other values remain the same. (1) Resistor should be placed adjacent to Pin 1.