LS7231 LSI | Alldatasheet
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DESCRIPTION: LS7231 through LS7234 are a series of monolithic, MOS integrated circuits designed for the control of brightness of incandescent lamps. The outputs of these ICs control the brightness of a lamp by controlling the firing angle of a triac connected in series with the lamp. All internal timings are synchronized with the line frequency by means of a built-in phase-lock loop circuit. The output occurs once every half-cycle of the line frequency. Within the half- cycle, the output can be positioned anywhere between 158˚conduction angle for maximum brightness and 41˚ conduction angle for minimum brightness in relation to the AC line frequency. The positioning of the output is con- trolled by applying a low level at the SENS input or a high level at the EXT input. These functions may be implemented with very few inter- face components, as shown in Figure 5. When imple- mented in this manner, touching of the Touch Plate caus- es the lamp brightness to change as follows: 1. If the Touch Plate is touched momentarily (42ms to 333ms), the lamp is: a) turned off if it was on, b) turned on if it was off. The brightness resulting is either full brightness or depending on the circuit type, a previous brightness stored in the IC memory. 2. If the Touch Plate is touched for a prolonged time (more than 342ms) the light intensity changes slowly. As long as the touch is maintained, the change con- tinues; the direction of change reverses whenever the maximum or minimum brightness is reached. LSI TRIG V DD (-V) EXT SENS V SS (+V) DOZE CAP SYNC LS7231-34 FIGURE 1 PIN ASSIGNMENT - TOP VIEW The IC also provides an input for slow dimming. By applying a slow clock to this input, the lamp can be dimmed slowly until total turn off occurs. This fea- ture can be useful at bedtime in a child’s room. INPUT/OUTPUT DESCRIPTION: VSS (Pin 1) Supply voltage positive terminal. DOZE (Pin 2) A clock applied to this input causes the brightness to de- crease in equal increments with each negative transition of the clock. Eventually, when the lamp turns off, this in- put has no further effect. The lamp can be turned on again by activating either the SENS input or the EXT in- put. For the transition from maximum brightness to off, a total of 83 clock pulses are needed at the DOZE input. When either the SENS or the EXT input is active, the DOZE input is disabled. (See Figure 7) CAP (Pin 3) The CAP input is for the PLL filter capacitor. A 0.047µF capacitor should be connected to this input. 7231-4-120100-1 December 2000 FEATURES:
- Phase-lock loop synchronization allows use in Wall Switch applications.
- Provides brightness control of incandescent lamps with touch plates or mechanical switches.
- Controls the "duty cycle" from 23% to 88% (conduction angles for AC half-cycles between 41˚ and 158˚, respectively.)
- Operates at 50Hz/60Hz line frequency.
- Extension input for remote activation.
- Input for slow dimming.
- +12V to +18V DC Power Supply voltage. (VSS - VDD )
- LS7231 to LS7234 (DIP) - See Figure 1 LS7231-S to LS7234-S (SOIC) LSI/CSI LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747 (631) 271-0400 FAX (631) 271-0405 LS7231-7234 U L® A3800
ABSOLUTE MAXIMUM RATINGS: PARAMETER SYMBOL VALUE UNIT DC Supply Voltage VSS +20 V Any Input Voltage VIN VSS -20 to VSS + 0.5 V Operating Temperature TA 0 to +80 ˚C Storage Temperature TSTG -65 to +150 ˚C DC ELECTRICAL CHARACTERISTICS: (TA = 25˚C, all voltages referenced to VDD ) PARAMETER SYMBOL MIN TYP MAX UNIT CONDITION Supply Voltage VSS +12 – +18 V - Supply Current ISS – 1.0 1.4 mA VSS = +15V, output off Input Voltages: DOZE LO VIZL 0 – VSS -6 V - DOZE HI VIZH VSS -2 – VSS V - SYNC LO VIRL 0 – VSS -9.5 V - SYNC HI VIRH VSS -5.5 – VSS V - SENS LO VIOL 0 – VSS -8 V - SENS HI VIOH VSS -2 – VSS V - EXT LO VIVL 0 – VSS -8 V - EXT HI VIVH VSS -2 – VSS V - Input Current: SYNC, SENS, EXT HI IIH – – 110 µA With Series 1.5MΩ Resistor to 115VAC Line SYNC, SENS, EXT LO IIL – – 100 nA - DOZE HI IIH – – 100 nA - DOZE LO IIL – – 100 nA - TRIG HI Voltage VOH – VSS – V - TRIG LO Voltage VOL – VSS -8 – V VSS = +15V TRIG Sink Current IOS 25 – – mA 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 SYMBOL MIN TYP MAX UNIT SYNC Frequency fs 40 - 70 Hz SHORT TOUCH TS1 42 - 333 ms (ON/OFF Operation) LONG TOUCH TS2 342 - infinite ms (Dimming Operation) DOZE Frequency - - - 500 Hz TRIG Pulse Width TW - 33 - µs TRIG Conduction-Angle Ø 41 - 158 degrees (Note 1) Ø Period (Max to Max in - - 7.64 - seconds continuous dimming) A1B1 = B2A2 duration - - 934 - ms B1B2 Min. intensity dwell- - 500 - ms NOTE 1 . In the circuit 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. 7231-34-041195-3
FIGURE 2. TRIG OUTPUT CONDUCTION ANGLE, Ø, VS SENS INPUT
(1) For Connection A. Use 0.22µF for Connection B. (2) For Connection A. Use 1/4W for Connection B. (3) For Connection A. Use 0.1µF for Connection B. (4) For Connection A. Use 1/4W for Connection B. FIGURE 5. A Typical Lamp Dimmer NOTES 1) All circuits connected by broken lines are optional. 2) C7 is used only with electronic extension and R7 is used only with mechanical switch. 3) Connection between Pin 1 & Pin 2 should be broken when DOZE circuit is used. 4) Use Connection A when Neutral is not available. Use Connection B when Neutral is available. 5) Connection between Pin 6 & Pin 7 should be broken when EXT is used.
FIGURE 8. A SWITCH-OPERATED LAMP DIMMER
- Foot-Switch Dimmer for large floor lamps.
- Hand-Switch Dimmer for end-table lamps.