TDA1085C.PDF

Order this document by TDA1085C/D

The TDA1085C is a phase angle triac controller having all the necessary

functions for universal motor speed control in washing machines. It operates

in closed loop configuration and provides two ramp possibilities.

•

UNIVERSAL MOTOR

SPEED CONTROLLER

On–Chip Frequency to Voltage Converter

SEMICONDUCTOR

TECHNICAL DATA

•

On–Chip Ramps Generator

•

Soft–Start

•

Load Current Limitation

•

Tachogenerator Circuit Sensing

•

Direct Supply from AC Line

•

Security Functions Peformed by Monitor

D SUFFIX

PLASTIC PACKAGE

CASE 751B

(SO–16)

PLASTIC PACKAGE

CASE 648

ORDERING INFORMATION

Device

Operating

Temperature Range

Package

TDA1085CD

TDA1085C

T J = – 10

to +120

SO–16

Plastic DIP

Figure 1. Representative Block Diagram and Pin Connections

+ V CC

Shunt Regulator

Ballast Resistor

Voltage

Reg

Monitoring

Reset

Speed

Detector

–

Trigger Pulse

Gen.

Ramp

Generator

Control

Amp.

0.7 V

Current

Limiter

–V CC

4 5

14 15

Motorola, Inc. 1995

MOTOROLA ANALOG IC DEVICE DATA

TDA1085C

MAXIMUM RATINGS (T A = 25 ° C, voltages are referenced to Pin 8, ground)

Rating

Symbol

Value

Unit

Power Supply, when externally regulated, V Pin 9

V CC

Maximum Voltage per listed pin

Pin 3

Pin 4–5–6–7–13–14–16

Pin 10

V Pin

+ 5.0

0 to + V CC

0 to + 17

Maximum Current per listed pin

Pin 1 and 2

Pin 3

Pin 9 (V CC )

Pin 10 shunt regulator

Pin 12

Pin 13

I Pin

– 3.0 to + 3.0

– 1.0 to + 0

– 1.0 to + 1.0

– 200

Maximum Power Dissipation

P D

1.0

Thermal Resistance, Junction–to–Air

q JA

° C/W

Operating Junction Temperature

T J

– 10 to + 120

° C

Storage Temperature Range

T stg

– 55 to + 150

ELECTRICAL CHARACTERISTICS (T A = 25 ° C)

Characteristic

Symbol

Min

Typ

Max

Unit

VOLTAGE REGULATOR

Internally Regulated Voltage (V Pin 9 )

(I Pin 7 = 0, I Pin 9 + I Pin 10 = 15 mA, I Pin 13 = 0)

V CC

15.3

15.6

V CC Temperature Factor

—

– 100

—

ppm/ ° C

Current Consumption (I Pin 9 )

(V 9 = 15 V, V 12 = V 8 = 0, I 1 = I 2 = 100 m A,

all other pins not connected)

I CC

—

4.5

6.0

V CC Monitoring Enable Level

V CC Monitoring Disable Level

V CC EN

V CC DIS

—

V CC – 0.4

V CC – 1.0

—

RAMP GENERATOR

Reference Speed Input Voltage Range

V Pin 5

0.08

—

13.5

Reference Input Bias Current

– I Pin 5

0.8

1.0

Ramp Selection Input Bias Current

– I Pin 6

—

1.0

Distribution Starting Level Range

V DS

—

2.0

Distribution Final Level

V Pin 6 = 0.75 V

V DF /V DS

2.0

2.09

2.2

High Acceleration Charging Current

V Pin 7 = 0 V

V Pin 7 = 10 V

– I Pin 7

1.0

—

1.2

1.7

1.4

Distribution Charging Current

V Pin 7 = 2.0 V

– I Pin 7

4.0

5.0

6.0

m A

MOTOROLA ANALOG IC DEVICE DATA

TDA1085C

ELECTRICAL CHARACTERISTICS (continued)

Characteristic

Symbol

Min

Typ

Max

Unit

CURRENT LIMITER

Limiter Current Gain — I Pin 7 /I Pin 3

(I Pin3 = – 300 m A)

C g

130

180

250

Detection Threshold Voltage

I Pin 3 = – 10 m A

V Pin 3 TH

FREQUENCY TO VOLTAGE CONVERTER

Input Signal “Low Voltage”

Input Signal “High Voltage”

Monitoring Reset Voltage

V 12 L

V 12 H

V 12 R

–100

+100

5.0

—

Negative Clamping Voltage

I Pin 12 = – 200 m A

– V 12 CL

—

0.6

—

Input Bias Current

– I Pin12

—

m A

Internal Current Source Gain

G.0

9.5

—

I Pin 4

I Pin 11

, V Pin 4 V Pin 11 0

Gain Linearity versus Voltage on Pin 4

(G 8.6 = Gain for V Pin 4 = 8.6 V)

V 4 = 0 V

V 4 = 4.3 V

V 4 = 12 V

G/G 8.6

1.04

1.015

0.965

1.05

1.025

0.975

1.06

1.035

0.985

Gain Temperature Effect (V Pin 4 = 0)

—

350

—

ppm/

Output Leakage Current (I Pin 11 = 0)

– I Pin 4

—

100

CONTROL AMPLIFIER

Actual Speed Input Voltage Range

V Pin 4

—

13.5

Input Offset Voltage V Pin 5 – V Pin 4

(I Pin 16 = 0, V Pin 16 = 3.0 and 8.0 V)

V off

—

Amplifier Transconductance

(I Pin 16 /

270

340

400

A/V

(V 5 – V 4 )

(I Pin 16 = + and – 50

A, V Pin 16 = 3.0 V)

Output Current Swing Capability

Source

Sink

I Pin 16

m A

– 200

– 100

100

– 50

200

Output Saturation Voltage

V 16 sat

—

0.8

TRIGGER PULSE GENERATOR

Synchronization Level Currents

Voltage Line Sensing

Triac Sensing

m A

I Pin 2

I Pin 1

—

± 50

± 100

Trigger Pulse Duration (C Pin 14 = 47 nF, R Pin 15 = 270 k W)

T p

—

m s

Trigger Pulse Repetition Period, conditions as a.m.

T R

—

220

—

m s

Output Pulse Current V Pin 13 = V CC – 4.0 V

– I Pin 13

180

192

—

Output Leakage Current V Pin 13 = – 3.0 V

I 13 L

—

m A

Full Angle Conduction Input Voltage

V 14

—

11.7

—

Saw Tooth “High” Level Voltage

V 14 H

—

12.7

Saw Tooth Discharge Current, I Pin15 = 100 m A

I Pin 14

—

105

m A

MOTOROLA ANALOG IC DEVICE DATA

TDA1085C

GENERAL DESCRIPTION

The TDA 1085C triggers a triac accordingly to the speed regulation

requirements. Motor speed is digitally sensed by a tachogenerator

and then converted into an analog voltage.

The speed set is externally fixed and is applied to the internal linear

regulation input after having been submitted to programmable

acceleration ramps. The overall result consists in a full motor speed

range with two acceleration ramps which allow efficient washing

machine control (Distribute function).

Additionally, the TDA 1085C protects the whole system against AC

line stop or variations, overcurrent in the motor and tachogenerator

failure.

INPUT/OUTPUT FUNCTIONS

(Refer to Figures 1 and 8)

Voltage Regulator – (Pins 9 and 10) This is a parallel type regulator

able to sink a large amount of current and offering good

characteristics. Current flow is provided from AC line by external

dropping resistors R1, R2, and rectifier: This half wave current is

used to feed a smoothering capacitor, the voltage of which is

checked by the IC.

When V CC is reached, the excess of current is derived by another

dropping resistor R10 and by Pin 10. These three resistors must be

determined in order:

Ramp Generator – (Pins 5, 6, 7) The true Set Speed value taken in

consideration by the regulation is the output of the ramp generator

(Pin 7). With a given value of speed set input (Pin 5), the ramp

generator charges an external capacitor C Pin 7 up to the moment

V Pin 5 (set speed) equals V Pin 4 (true speed), see Figure 2. The IC

has an internal charging current source of 1.2mA and delivers it from

0 to 12 V at Pin 7. It is the high acceleration ramp (5.0 s typical) which

allows rapid motor speed changes without excessive strains on the

mechanics. In addition, the TDA 1085C offers the possibility to break

this high acceleration with the introduction of a low acceleration ramp

(called Distribution) by reducing the Pin 7 source current down to

5.0

•

To let 1.0 mA flow through Pin 10 when AC line is minimum and V CC

consumption is maximum (fast ramps and pulses present).

A under Pin 6 full control, as shown by following conditions:

•

To let V 10 reach 3.0 V when AC line provides maximum current and

V CC consumption is minimum (no ramps and no pulses).

•

Presence of high acceleration ramp V Pin 5 > V Pin 4

Distribution occurs in the V Pin 4 range (true motor speed) defined

by V Pin 6 V Pin 4 2.0 V Pin 6

For two fixed values of V Pin 5 and V Pin 6 , the motor speed will have

high acceleration, excluding the time for V Pin 4 to go from V Pin 6

to two times this value, high acceleration again, up to the moment

the motor has r eached the set speed value, at which it will stay,

see Figure 3.

Should a reset happen (whatever the cause would be), the above

mentioned successive ramps will be fully reprocessed from 0 to the

maximum speed. If V Pin 6 = 0, only the high acceleration ramp

occurs.

To get a real zero speed position, Pin 5 has been designed in such a

way that its voltage from 0 to 80 mV is interpreted as a true zero. As

a consequence, when changing the speed set position, the designer

must be sure that any transient zero would not occur: if any, the entire

circuit will be reset.

As the voltages applied by Pins 5 and 6 are derived from the internal

voltage regulator supply and Pin 4 voltage is also derived from the

same source, motor speed (which is determined by the ratios

between above mentioned voltages) is totally independent from V CC

variations and temperature factor.

Control Amplifier – (Pin 16) It amplifies the difference between true

speed (Pin 4) and set speed (Pin 5), through the ramp generator. Its

output available at Pin 16 is a double sense current source with a

maximum capability of

•

All along the main line cycle, the Pin 10 dynamic range must not be

exceeded unless loss of regulation.

An AC line supply failure would cause shut down.

The double capacitive filter built with R1 and R2 gives an efficient

V CC smoothing and helps to remove noise from set speeds.

Speed Sensing – (Pins 4, 11, 12) The IC is compatible with an

external analog speed sensing: its output must be applied to Pin 4,

and Pin 12 connected to Pin 8.

In m ost o f t he applications it i s more c onvenient to use a digital

speed sensing with an unexpensive tachogenerator which

doesn 4 t need any tuning. During every positive cycle at Pin 12,

the capacitor C Pin 11 i s charged t o almost V CC and during this

time, Pin 4 delivers a current which is 10 times the one charging

C Pin 11 . The current source gain is called G and is tightly

specified, but nevertheless requires an adjustment on R Pin 4 . The

current into this resistor is proportional to C Pin 11 and to the motor

speed; being filtered by a capacitor, V Pin 4 becomes smothered

and represents the “true actual motor speed”.

To maintain linearity into the high speed range, it is important to verify

that C Pin 11 is fully charged: the internal source on Pin 11 has 100 K W

impedance. Nevertheless C Pin 11 has to be as high as possible as it

has a large influence on FV/C temperature factor. A 470 K W resistor

between Pins 11 and 9 reduces leakage currents and temperature

factor as well, down to neglectable effects.

Pin 12 also has a monitoring function: when its voltage is above

5.0 V, the trigger pulses are inhibited and the IC is reset. It also

senses the tachogenerator continuity, and in case of any circuit

aperture, it inhibits pulse, avoiding the motor to run out of control. In

the TDA 1085C, Pin 12 is negatively clamped by an internal diode

which removes the necessity of the external one used in the former

circuit.

100

A and a specified transconductance

A/V typical). Pin 16 drives directly the trigger pulse generator,

and must be loaded by an electrical network which compensates the

mechanical characteristics of the motor and its load, in order to

provide stability in any condition and shortest transient response; see

Figure 4.

This network must be adjusted experimentally.

In case of a periodic torque variations, Pin 16 directly provides the

phase angle oscillations.

MOTOROLA ANALOG IC DEVICE DATA

•

(340

TDA1085C

Trigger Pulse Generator – (Pins 1, 2, 5, 13, 14, 15)

This circuit performs four functions:

Pin 13 is the pulse output and an external limiting resistor is

mandatory. Maximum current capability is 200 mA.

•

The conversion of the control amplifier DC output level to a

proportional firing angle at every main line half cycle.

Current Limiter – (Pin 3) Safe operation of the motor and triac under

all conditions is ensured by limiting the peak current. The motor

current develops an alternative voltage in the shunt resistor (0.05

in Figure 4). The negative half waves are transferred to Pin 3 which

is positively preset at a voltage determined by resistors R3 and R4.

As motor current increases, the dynamical voltage range of Pin 3

increases and when Pin 3 becomes slightly negative in respect to

Pin 8, a current starts to circulate in it. This current, amplified

typically 180 times, is then used to discharge Pin 7 capacitor and, as

a result, reduces firing angle down to a value where an equilibrium is

reached. The choice of resistors R3, R4 and shunt determines the

magnitude of the discharge current signals on C Pin 7 .

•

The calibration of pulse duration.

•

The repetition of the pulse if the triac fails to latch on if the current

has been interrupted by brush bounce.

•

The delay of firing pulse until the current crosses zero at wide firing

angles and inductive loads.

R Pin 15 programs the Pin 14 discharging current. Saw tooth signal is

then fully determined by R15 and C14 (usually 47 nF). Firing pulse

duration and repetition period are in inverse ratio to the saw tooth

slope.

Notice that the current limiter acts only on peak triac current.

APPLICATION NOTES

(Refer to Figure 4)

Printed Circuit Layout Rules

In the common applications, where TDA 1085C is used, there is on

the same board, presence of high voltage, high currents as well as

low voltage signals where millivolts count. It is of first magnitude

importance to separate them from each other and to respect the

following rules:

peak in order to have the largest signal/noise ratio without resetting

the integrated circuit (which occurs if V Pin 12 reaches 5.5 V). It must

be also verified that the Pin 12 signal is approximately balanced

between “high” (over 300 mV) and “low”. An 8–poles tacho is a

minimum for low speed stability and a 16–poles is even better.

The RC pole of the tacho circuit should be chosen within 30 Hz in

order to be as far as possible from the 150 Hz which corresponds to

the AC line 3rd harmonic generated by the motor during starting

procedure. In addition, a high value resistor coming from V CC

introduces a positive offset at Pin 12, removes noise to be interpreted

as a tacho signal. This offset should be designed in order to let Pin 12

reach at least – 200 mV (negative voltage) at the lowest motor speed.

We remember the necessity of an individual tacho ground

connection.

•

Capacitor decoupling pins, which are the inputs of the same

comparator, must be physically close to the IC, close to each other

and grounded in the same point.

•

Ground connection for tachogenerator must be directly connected

to Pin 8 and should ground only the tacho. In effect, the latter is a

first magnitude noise generator due to its proximity to the motor

which induces high d f /dt signals.

Frequency to Voltage Converter – F V/C

C Pin 11 has a recommended value of 820 pF for 8–poles tachos and

maximum motor rpm of 15000, and R Pin 11 must be always 470 K.

R Pin 4 should be choosen to deliver within 12 V at maximum motor

speed in order to maximize signal/noise ratio. As the FV/C ratio as

well as the C Pin 11 value are dispersed, R Pin 4 must be adjustable and

should be made of a fixed resistor in serice with a trimmer

representing 25% of the total. Adjustment would become easier.

Once adjusted, for instance at maximum motor speed, the FV/C

presents a residual non linearity; the conversion factor (mV per RPM)

increases by within 7.7% as speed draws to zero. The guaranteed

dispersion of the latter being very narrow, a maximum 1% speed

error is guaranteed if during Pin 5 network design the small set

values are modified, once forever, according this increase.

The following formulas give V Pin 4 :

•

The ground pattern must be in the “star style” in order to fully

eliminate power currents flowing in the ground network devoted to

capacitors decoupling sensitive Pins: 4, 5, 7, 11, 12, 14, 16.

As an example, Figure 5 presents a PC board pattern which

concerns the group of sensitive Pins and their associated capacitors

into which the a.m. rules have been implemented. Notice the full

separation of “Signal World” from “Power”, one by line AB and their

communication by a unique strip.

These rules will lead to much satisfactory volume production in the

sense that speed adjustment will stay valid in the entire speed

range.

Power Supply

As dropping resistor dissipates noticeable power, it is necessary to

reduce the I CC needs down to a minimum. Triggering pulses, if a

certain number of repetitions are kept in reserve to cope with motor

brush wearing at the end of its life, are the largest I CC user. Classical

worst case configuration has to be considered to select dropping

resistor. In addition, the parallel regulator must be always into its

dynamic range, i.e., I Pin 10 over 1.0 mA and V Pin 10 over 3.0 V in any

extreme configuration. The double filtering cell is mandatory.

V Pin 4 G.0 (V CC –V a ) C Pin 11 R 4 f (1 120k

R Pin11 )

In volts.

G.0 . (V CC – V a ) 140

V a = 2.0 V BE

120 k = R int , on Pin 11

Tachogenerator Circuit

The tacho signal voltage is proportional to the motor speed. Stablility

considerations, in addition, require an RC filter, the pole of which

must be looked at. The combination of both elements yield a constant

amplitude signal on Pin 12 in most of the speed range. It is

recommended to verify this maximum amplitude to be within 1.0 V

Speed Set – (Pin 5) Upon designer choice, a set of external

resistors apply a series of various voltages corresponding to the

various motor speeds. When switching external resistors, verify that

no voltage below 80 mV is ever applied to Pin 5. If so, a full circuit

reset will occur.

MOTOROLA ANALOG IC DEVICE DATA

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