5-SPEED AC MOTOR CONTROLLER / 5-STEP LAMP DIMMER

FEATURES:

• Inputs/Outputs for selecting and displaying 5 speed/power levels

Electronically latched inputs with dome switch compatibility

• Separate Boost input for full-speed/power selection

• Separate Pulse input for periodic on/off cycle selection

• LS7317 (DIP); LS7317-S (SOIC) -See Figure 1-

Applications:

• Consumer Appliances such as Blenders, Range Hoods, Fans, etc.

• Lamp Dimmer for control of high-voltage lamps and electronic-transformer

coupled low-voltage lamps such as Halogen Lamps.

DESCRIPTION:

The LS7317 is a MOS circuit for controlling the speed of an AC motor.

Five inputs, PL1/ through PL5/ are provided to select five speed/power

levels between 40% and 96% of full power. A BOOST/ input is provided to

override any selected power level with a jump to 99% of full power.

A PULSE/ input provides for periodic two seconds on, two seconds off

auto-pulse cycle for one minute. All these inputs require momentary ac-

tivation which can very conveniently be produced by push-button dome or

leaf switches. When a logic low is applied through such a push-button

switch to any of the speed inputs or the Pulse input, the input becomes

active and switches state to become an output for driving an external LED

and display the selected speed level. A TRIG/ output is also turned on to

drive the trigger input of a triac in series with the motor and control its

speed by controlling the firing angle of the triac. Phase synchronization of

the external AC and the triac trigger is made with an internal PLL, with the

AC signal being applied to the SYNC input of the LS7317. An OFF/ input

is provided for turning the motor off with a momentary push-button switch.

The LS7317 can also be used as a Lamp Dimmer providing 5 selectable

intensity levels as indicated in the application schematic shown in Figure

5. The LOAD can be either a high voltage lamp or the input to an

electronic-transformer coupling to a low-voltage lamp. In the Lamp Dim-

mer application, the Pulse/ and Boost/ inputs are not used

INPUTS/OUTPUTS

PL1/ - PL5/ (Pin 1 - Pin 5)

Five inputs/outputs for selecting five speed/power levels. When no power

level is selected, such as upon a system power-up, PL1/ - PL5/ all act as

inputs. When a power level is selected by applying a logic low at one of

these inputs for the duration of TH (see Transient Characteristics section),

the output TRIG/ is turned on at the selected phase angle and the PL/ in-

put switches state to become a current-sinking output in order to drive a

display, such as an LED. It switches back to the input state when another

PL/ input or the OFF/ input is activated.

Power levels and triac conduction angles referenced to the SYNC input

(Pin 10) for each PL/ and Boost/ are shown in Table 1.

TABLE 1

PL1/

PL2/

PL3/

PL4/

PL5/

BOOST/

% of Full Power:

40%

55%

69%

82%

96%

99%

Conduction Angle

81

°

95

°

108

°

122

°

147

°

160

°

November 2005

7317-112405-1

LSI/CSI

LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747 (631) 271-0400 FAX (631) 271-0405

LS7317

UL

®

A3800

PULSE/ (Pin 6)

A logic low applied to the PULSE/ input initiates the auto-pulse

cycle and causes the PULSE/ input to switch from an input to

an output state. Subsequently, when a speed level is selected,

the TRIG/ output is turned on for two seconds, then turned off

for two seconds. The two second on, two second off cycle is

repeated for one minute. At the end of one minute the auto-

pulse cycle is terminated with the TRIG/ output off and the

PULSE/ pin reverting back to the input state.

BOOST/ (Pin 7)

A logic low applied to the BOOST/ input causes the TRIG/ out-

put to be turned on at the maximum conduction angle, cor-

responding to 99% of full power. The boost state overrides any

prevalent state and continues as long as the BOOST/ input is

held at logic low. Upon returning BOOST/ to logic high, the cir-

cuit returns to and continues in the pre-Boost state.

OFF/ (Pin 9)

A logic low applied to the OFF/ input turns the TRIG/ output off,

aborts any auto-pulse cycle in progress and causes any active

PL/ pin or the PULSE/ pin to switch from the output to the input

state.

CAP (Pin 8)

Input for the PLL external filter capacitor connection.

SYNC (Pin 10)

Input for the PLL 50Hz/60Hz AC reference signal.

All internal timings are synchronized with the SYNC input.

TRIG/ (Pin 12)

The TRIG/ output is designed to drive the gate of a triac con-

nected in series with the load. When on, the TRIG/ output pro-

duces a 1.2ms/1ms wide negative pulse in each half-cycle of

the 50Hz/60Hz AC at a predefined phase angle which cor-

responds to the selected speed level. When off, TRIG/ sits at

logic high.

1

2

3

4

5

6

7

8

9

10

11

12

13

14

PL1/

PL2/

PL3/

PL4/

PL5/

TRIG/

SYNC

CAP

PULSE/

OFF/

CONNECTION DIAGRAM - TOP VIEW

FIGURE 1

BOOST/

NC