LSI/CSI UL LS7237 LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747 (631) 271-0400 FAX (631) 271-0405 ® A3800 January 2003 TOUCH CONTROL LAMP STEP DIMMER V SS (+V) 1 MODE 2 CAP 3 SYNC 4 LS7237 DESCRIPTION: LS7237 is a MOS integrated circuit designed to control the brightness of an incandescent lamp. The output of the LS7237 triggers a triac connected in series with a lamp (See Figure 5). The lamp brightness is determined by controlling the output conduction angle (triac triggering angle) in relation to the AC line frequency (See Figure 2). PIN ASSIGNMENT - TOP VIEW STANDARD 8 PIN PLASTIC DIP LSI FEATURES: • PLL synchronization allows use as a Wall Switch • Provides brightness control of an incandescent lamp with a touch plate or pushbutton switch • Can control speed of shaded pole and universal AC motors • Controls the "duty cycle" from 23% to 88% (conduction angles for AC half-cycles between 45˚ and 158˚, respectively) • Operates at 50Hz/60Hz line frequency • Extension input for remote activation • +12V to +18V (VSS - VDD) • LS7237 (DIP); LS7237-S (SOIC) - See Figure 1 8 TRIG 7 V DD (-V) 6 EXT 5 SENS FIGURE 1 INPUT/OUTPUT DESCRIPTION: The output conduction angle can be varied by applying a low level pulse at the SENS input or a high level pulse at the EXT input. When implemented as shown in Figure 5, this is accomplished by touching the Touch Plate which causes the lamp brightness to change in specified steps as follows: LEVEL Off Night Light Mood Light Medium Maximum BRIGHTNESS (% Rated Wattage) 0 9 29 66 99 The LS7237 can operate in one of three different modes selected by the MODE input. The Brightness Sequences produced by the different modes are as follows: MODE 0 1 2 BRIGHTNESS SEQUENCE Off-Max-Off Off-Mood-Med-Max-Off Off-Night-Mood-Med-Max-Off After AC power-up, the output comes up in the OFF state. Following that, every time the Touch Plate is touched, the output steps to the next level of brightness. The next step following the maximum brightness is the OFF state, initiating a new sequence. 7237-012703-1 VSS (Pin 1) Supply voltage positive terminal. MODE (Pin 2) The operating mode for the circuit is selected by connecting this input as follows: MODE INPUT VSS VDD Float SELECTED MODE Mode 0 Mode 1 Mode 2 CAP (Pin 3) PLL filter input capacitor. A 0.047µF capacitor should be connected to this input. SYNC (Pin 4) The AC Line Frequency is applied to this input through an external RC circuit (See Figure 5). The Phase-Lock Loop in the IC synchronizes all internal timings to the AC signal at the SYNC input. SENS (Pin 5) A low-level pulse applied to this input causes the TRIG output to step to the next conduction angle in the sequence selected by the MODE input. The change in conduction angle takes place with the trailing edge of the SENS input pulse. EXT (Pin 6) CONDUCTION ANGLE, Ø The EXT input is functionally similar to the SENS input with No output the exception that a high-level pulse is the active signal. It is 45˚ recommended that the EXT input be used instead of the 70˚ SENS input when long extension wires are used between the 105˚ IC and the sensing circuitry (See Figure 5 and Figure 6) be158˚ cause the EXT input is less susceptible to “Noise”. BRIGHTNESS LEVEL Off Night Light Mood Light Medium Maximum NOTE: In the schematic shown in Figure 5, the SYNC Input signal is delayed in phase with respect to the AC Line by about 7°. This delay reduces the conduction angle, Ø with respect to the AC Line by 7° from the values shown above. VDD (Pin 7) Supply voltage negative terminal. TRIG (Pin 8) The TRIG output is a low-level pulse of fixed duration occurring once every half-cycle of the SYNC input. The conduction angle, Ø of the output in relation to the SYNC signal controls the lamp brightness. The 5 levels of brightness correspond to the 5 values of Ø as follows: 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. SYNC ø TRIG TW TW FIGURE 2. TRIG OUTPUT CONDUCTION ANGLE, Ø TS1 SENS 158˚ Ø, MODE 0 OFF 158˚ OFF 158˚ OFF 158˚ 105˚ 70˚ Ø, MODE 1 70˚ OFF OFF 158˚ 105˚ 70˚ 45˚ Ø, MODE 2 OFF OFF FIGURE 3. TRIG OUTPUT CONDUCTION ANGLE, Ø, VS SENS INPUT 7237-012703-2 ABSOLUTE MAXIMUM RATINGS: PARAMETER SYMBOL DC Supply Voltage VSS Any Input Voltage VIN Operating Temperature TA Storage Temperature TSTG VALUE +20 VSS -20 to VSS +0.5 0 to +80 -65 to +150 UNIT V V ˚C ˚C DC ELECTRICAL CHARACTERISTICS: (TA = 25˚C, all voltages referenced to VDD) PARAMETER Supply Voltage Supply Current SYMBOL VSS ISS MIN +12 – TYPE – 1.0 Input Voltages: MODE LO MODE HI SYNC LO SYNC HI SENS LO SENS HI EXT LO EXT HI VIZL VIZH VIRL VIRH VIOL VIOH VIVL VIVH 0 VSS - 1.5 0 VSS - 5.5 0 VSS - 2 0 VSS - 2 – – – – – – – – Input Current: SYNC, SENS, EXT HI IIH – SYNC, SENS, EXT LO IL TRIG HI Voltage TRIG LO Voltage TRIG Sink Current VOH VOL IOS MAX +18 1.4 UNIT V mA CONDITION VSS = +15V, output off VSS - 9 VSS VSS - 9.5 VSS VSS - 8 VSS VSS - 8 VSS V V V V V V V V - – 110 µA – – 100 nA – – 25 VSS VSS - 8 – – – – V V mA With Series 1.5MΩ Resistor to 115VAC Line VSS = +15V VSS = +15V VOL = VSS - 4V TIMING CHARACTERISTICS (See Figures 2 and 3): All timings are based on fs = 60Hz, unless otherwise specified. 50Hz timings are 1.2 times 60Hz timings. PARAMETER SYNC Frequency SENS/EXT Duration SYMBOL fs TS1 MIN 40 50 TRIG Pulse Width TW - SYNC CAP MODE 7237-012703-3 4 BUF PHASE LOCK LOOP 3 2 BUF EXT 6 BUF SENS 5 BUF VSS 1 (+V) VDD 7 (-V) TYPE 33 MAX 70 Infinite - UNIT Hz ms µs Ø MEMORY DIGITAL COMPARATOR CONTROL LOGIC Ø POINTER FIGURE 4 LS7237 BLOCK DIAGRAM OUTPUT DRIVER 8 TRIG APPLICATION EXAMPLES: A typical implementation of a lamp dimmer circuit is shown in Fig. 5. Here the brightness of the lamp is set by touching the Touch Plate . The functions of different components are as follows: TOUCH PLATE *R 2KΩ ,1/4W EXTN • The 15V DC supply for the chip is provided by Z, D1, R1, C2, C5. • R2 and C4 generate the filtered signal for the SYNC input for synchronizing the internal PLL with the line frequency. • R3 and C7 act as filter circuit for the electronic extension. If extensions are not used, the EXT input (Pin 6) should be tied to VDD (Pin 7). • R4, R5, R6 set up the sensitivity of the SENS input. C6 provides noise filtering. • C3 is the filter capacitor for the internal PLL. • R8 provides current limiting and isolation between the chip output and the triac gate. • C1 and L are RF filter circuits. In the case of momentary power failure, the circuit state remains unchanged for a period up to 1 sec. For longer power interruptions, the output is shut off. *R IN914 MPS8599 *R *R = 2MΩ , 1/4W for 115VAC = 3.6MΩ , 1/4W for 220VAC 200K Ω ,1/4W P FIGURE 6. ELECTRONIC EXTENSION EXTENSIONS: All switching and dimming functions can also be implemented by utilizing the EXT input. This can be done by either a pushbuttonl switch or the electronic switch in conjunction with a Touch Plate as shown in Figure 6. When the plate is touched, a logic high level is generated at the EXT input of the IC for both half-cycles of the line frequency. (See Figure 5) FIGURE 5. A Typical Lamp Dimmer P P SEE NOTE 2 MT2 C7 R8 G MT1 T Z R7 EXTN R3 + C5 - ELECTRONIC EXTENSION (FIG. 6) SEE NOTE 4 D1 L 115VAC OR 220VAC R6 C1 8 7 6 5 TRIG VDD EXT SENS C2 R5 TOUCH PLATE LS7237 R1 R2 VSS MODE CAP SYNC 1 2 3 4 A C3 B 1) 2) 3) 4) R4 NOTES: All circuits connected by broken lines are optional. C7 is used only with electronic extension and R7 is used only with mechanical switch Use Connection A when Neutral is not available. Use Connection B when Neutral is available. Connection between Pin 6 and Pin 7 should be broken when EXT is used. C1 = 0.15µF, 200V (1) C2 = 0.33µF, 200V C3 = 0.047µF, 25V C4 = 470pF, 25V C5 = 47µF, 25V C6 = 680pF, 25V C7 = 0.1µF, 25V (2) R1 = 270Ω, 1W R2 = 1.5MΩ, 1/4W R3 = 1.5MΩ, 1/4W 115V R4 = 1MΩ to 5MΩ, 1/4W (Select for sensitivity) R5, R6 = 2.7MΩ, 1/4W R7 = 150kΩ, 1/4W R8 = 100Ω, 1/4W D1 = IN4148 Z = 15V, 1W (Zener) T = Q4006L4 Triac (Typical) L = 100µH (RFI Filter) (1) For Connection A. Use 0.22µF for Connection B. (2) For Connection A, Modes 1 and 2. Use 1/4W for Mode 0 and Connection B, all Modes. 7237-012703-4 C6 SEE NOTE 3 LOAD N C4 C1 = 0.15µF, 400V (3) C2 = 0.22µF, 400V C3 = 0.047µF, 25V C4 = 470pF, 25V C5 = 47µF, 25V C6 = 680pF, 25V C7 = 0.1µF, 25V (4) R1 = 1kΩ, 2W R2 = 1.5MΩ, 1/4W R3 = 1.5MΩ, 1/4W 220V R4 = 1MΩ to 5MΩ, 1/4W (Select for sensitivity) R5, R6 = 4.7MΩ, 1/4W R7 = 150kΩ, 1/4W R8 = 100Ω, 1/4W D1 = 1N4148 Z = 15V, 1W (Zener) T = Q5004L4 Triac (Typical) L = 200µH (RFI Filter) (3) For Connection A. Use 0.1µF for Connection B. (4) For Connection A, Modes 1 and 2. Use 1/4W for Mode 0 and Connection B, all Modes.