ST STCC08 User Manual

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Features

■ 3.3 V and 5 V power supply compatible

■ ACS, ACST, TRIAC compatible

■ Gate driver output: 28 mA max sink current

■ Adjustable gate drive current

■ Sense the AC switch voltage in both AC line

polarities

■ Diode mode failure detection for solid state AC

switches

■ Short circuit failure detection for AC switches,

relays, electromechanical switches

■ Open AC switch detection for AC switches,

relays, electromechanical switches

■ SO-8 SMD package

STCC08

AC switch failure mode detector

SO-8

Applications

■ Home appliances

■ ACS, ACST, TRIAC drive

■ AC switch failure modes detection

■ Zero voltage synchronization

Benefits

■ Enable appliances to meet IEC 60335-1 and

IEC 60730-1 standards

■ Enable appliances to meet IEC 61000-4-4

standard

■ Eliminates high DC current in inductive load, by

detecting the diode mode failure

■ Improve system safety monitoring open switch

failure with critical loads such as door locks

■ Enable MCU to sense all AC switch failure

modes and protect the appliance

■ Less MCU pin allocated to AC failure detection

multiple STCC08 designed with resistor dividers uses one I/O

■ Easy to drive with MCU directly connected or

through an opto coupler

■ Highly compact with integrated solution in SMD

version

Description

The STCC08 is an AC switch failure mode detector and an AC power switch driver. It drives the AC switch and informs the MCU of switch failure. The MCU takes the appropriate actions to put the system in a secure state.

Diode-mode, short circuit detection and open switch in both AC line polarities are detected.

The STCC08 helps home appliances to meet the IEC 60335-1 safety standard.

The STCC08 can be easily interfaced to an MCU with its CMOS input AC switch driver and CMOS compatible output for the failure mode detector.

March 2008 Rev 1 1/13

www.st.com

Characteristics STCC08

1 Characteristics

Figure 1. Circuit block diagram

POWER SWITCH

SIGNAL SHAPING

Table 1. Circuit pin descriptions

GATE DRIVER

AVF DRIVER

Symbol Type Description

IN SIGNAL Logic AC switch drive

AVF SIGNAL Alternating voltage feedback: AC switch status output

AC SIGNAL AC switch status sense input

POWER Positive power supply

G SIGNAL AC switch gate driver output

AVF

GND

SIGNAL AC switch gate current setting

GND POWER Power supply reference

Figure 2. Pin layout (top view)

AVF

N/C

2/13

GND

STCC08 Characteristics

Table 2. Pin allocations

Pin # Name Description

1 IN Logic AC switch drive

2 AVF Alternating voltage feedback: AC switch status output

3 N/C Not connected

4 AC AC switch status sense input

6 G AC switch gate driver output

Positive power supply

AC switch gate current setting

8 GND Power supply reference

Table 3. Absolute ratings (T

= 25 °C unless otherwise stated, respect to GND)

amb

Symbol Pin Parameter name and conditions Value Unit

AVF

IN Switch activation voltage -0.3V to VCC +0.3 V

G Sunk driver current 30 mA

AC Input sense current peak 2.2 mA

AVF Alternative feedback voltage -0.3 to V

AVF Maximum feedback current 5 mA

Power supply voltage 0 to 6 V

+0.3 V

Junction temperature range -20 to 125 °C

Table 4. Recommended operating conditions

All

Storage junction temperature range -40 to 150 °C

Symbol Pin Parameter name and conditions Value Unit

G Max. sunk driver gate current 28 mA

RIG Gate current setting resistor 30 Ω

Power supply voltage respect to GND 2.97 to 5.5 V

Detector resistance for AC line = 120 V 100 kΩ

Detector resistance for AC line = 230 V 300 kΩ

SHUNT

AMB

HV biasing resistance for AC line = 120 V 100 kΩ

HV biasing resistance for AC line = 230 V 300 kΩ

All Operating ambient temperature range -20 to 85 °C

All Operating junction temperature range -20 to 125 °C

3/13

Characteristics STCC08

Table 5. Electrical characteristics

Symbol Pin Name Conditions Min Typ Max Unit

Switch drive (respect to GND, Tj=25 °C unless otherwise specified, RIG=30 Ω)

QUIESCENTVCC

OFF

Quiescent current IN = GND 2 mA

On-state switch

activation voltage

Off-state switch

release voltage

0.7*V

0.3*V

IN Input drive current Vin > V

G Gate drive current Vin > V

20 28 mA

AC Detection threshold 82 236 µA

Status output (respect to GND, T

Minimum output

AVF

voltage

=25 °C unless otherwise specified)

= 50 µA 0.7*V

AVF

= 50 µA

(CMOS Compatible)

AVF Maximum drop voltage

AVF

= 5 mA

(Opto-transistor

50 µA

0.3*V

compatible)

Table 6. Thermal resistance

Symbol Parameter name and conditions Value Unit

TH (j-a)

Table 7. System related electromagnetic compatibility ratings

SMD Thermal resistance Junction to Ambient 140 °C/W

Symbol Node Pin Parameter name and conditions Value Unit

ESD protection, IEC 61000-4-2, per input, against air

discharge

Neutral

ESD

Gate through ACS; ESD protection, IEC 61000-4-2, pin to ground, against air discharge

±8 kVG

Line AC

ESD

Neutral V

Neutral

PPB

Line AC

1. System oriented test circuits - see Application note AN2716

Alternating current through R IEC 61000-4-2, pin to ground, against air discharge

ESD protection, IEC 61000-4-2, pin to ground, for contact

discharge

Total Peak Pulse Voltage Burst, IEC 61000-4-4

Gate through ACS; Total Peak Pulse Voltage Burst, IEC

61000-4-4

(1)

Alternating current through RAC; Total Peak Pulse Voltage Burst, IEC 61000-4-4

4/13

(1)

= 300 kΩ; ESD protection,

±6 kV

(1)

±4 kV

STCC08 Functional description

2 Functional description

STCC08 functional description

The STCC08 is a power circuit designed to drive up to 10 mA IGT AC switches and to detect AC switch failure modes through MCU diagnostic.

It embeds a logic switch driver, an AC switch diode mode detection, a short circuit detection and an AC switch open detection.

STCC08 can be powered by a 3.3 V or 5 V power supply voltage.

Switch driver

This driver is a logic level buffer (CMOS compatible) interfacing directly with the AC switch and the microcontroller.

The AC switch must be driven in negative polarity: AC switch COM = A

= V

The drive Boolean rule is:

> Von: switch = ON

< Von: switch = OFF

The AC switch can be driven in continuous, pulsed or angle phase modes.

In insulated applications, the input can be driven through an opto-coupler powered with a non-insulated auxiliary power supply.

pin allows the AC switch gate current to be set. A resistor must be connected between

this pin and the ground GND. This resistor is defined according to the miminmum ambient temperature and the AC switch I

(see Figure 3). This optimizes the consumption of the

application.

Figure 3. R

= f(T

130

120

110

100

-20 -15 -10 -5 0 5 10 15 20 25 30

amb_min

(Ω)

IG_Max

AC switch 10 mA @ 25 °C AC switch 5 mA @ 25 °C

) for 5/10 mA AC switches

_min (°C)

amb

5/13

Functional description STCC08

Failure mode detection

This function detects AC switch failure modes required by the IEC 60335 standard:

● The AC switch diode mode failure in both negative and positive AC line polarities

This failure is simulated with a diode placed in parallel with the power switch according to the IEC 60335-1 standard.

● The AC switch short-circuit failure mode, any external shorting and any spurious power

switch turn-on

● The open AC switch failure mode

This function improves the system safety. A diode mode failure, a short circuit or an AC switch open can lead to dangerous situations for the system or the user.

The AVF block monitors the state of the AC switch in both AC polarities. Its output AVF is transmitted to the MCU for failure detection.

The MCU detects the failure according to the following truth table:

Table 8. STCC08 status truth table with R

IN (MCU generated) AVF MCU DIAGNOSTIC

0 Open collector AC switch OK

in parallel with the load

SHUNT

0 Open collector to 0 toggle Diode mode

0 0 Short AC switch

10AC switch OK

1 Open collector Open AC switch

For a diode mode, the AVF output toggles from open collector to GND each the half of the AC mains. Therefore, the AVF output is a pulsed signal during a diode mode failure.

The MCU can put the system in a safe configuration, switching off the front end relay already existing in home appliance designs.

Status reading

The AVF output is an open collector, active at low level. It can either be connected to a MCU input, in pull up input configuration, or through an opto-coupler in insulated designs.

For inductive loads, there is a phase shift between load current and AC line voltage. When the ACS control is removed:

● The AC switch - latch structure - still conducts and the AVF is at low level until the next

zero current crossing.

● The AVF is at low level until next zero current crossing.

● In the worst case, the load current crosses zero close to peak mains voltage. Then the

AVF signal should be read at peak mains voltage.

6/13

STCC08 Functional description

Figure 4. Failure mode detection for inductive loads in DC control mode

DIODE MODE

AC LINE

LOAD CURRENT

AVF

SUGGESTED

READING TIME

NORMAL MODE

SHORT CIRCUIT

The microcontroller can store the AC switch drive signal in a RAM register when it is driving the STCC08 input. Therefore it can save gate energy while determining conduction state from this RAM register and multiplexing this information with AVF signal.

AC LINE: High voltage between AC line and neutral

LOAD CURRENT: Current through the AC load

IN: MCU output driving the STCC08 IN input.

AVF: Alternating voltage feedback, output of the STCC08

7/13

Application information STCC08

3 Application information

Figure 5. Application example with an MCU direct drive + ACS

NEUTRAL

ACS

LOAD

LINE

SHUNT

The placement of a 100 nF capacitor between V advised. SW is an electromechanical switch that is part of the application design, for example, the water sensor in a washing machine.

3.1 Recommendations

The STCC08 is designed for 5 and 10 mA ACSs, ACSTs and TRIACs.

STCC08 basic application

POWER SWITCH

SIGNAL SHAPING

3.3V to 5V

GATE DRIVER

AVF DRIVER

and GND close to the STCC08 is

AVF

GND

MCU

The microcontroller reads the AC switch state from the AVF output of the STCC08. The microcontroller can power-off the application driving a front-end relay.

Figure 6. Non-insulated application

NEUTRAL

ACS

LOAD

LINE

SHUNT

FRONT END RELAY

8/13

POWER SWITCH

SIGNAL SHAPING

GATE DRIVER

AVF DRIVER

SAFETY TURN OFF

3.3V to 5V

AVF

GND

MCU

STCC08 Application information

This function is effective whatever the drive and the nature of the load.

Figure 7. ACS benefits

NEUTRAL

ACS

MAX=VCL

AC1

AC2

The ACS clamping capability, from 800 V to 1100 V reduces the stress across R

resistors

during an AC line over-voltage. This provides a robust solution and allows setting high voltage resistors R

to withstand the ACS clamping voltage instead of the AC line

maximum over-voltage.

STCC08 AVF alarms configuration

Figure 8. Open load and Short circuit ACS discrimination

LINE

NEUTRAL

SHUNT

ACS

LOAD

POWER SWITCH

SIGNAL SHAPING

GATE DRIVER

AVF DRIVER

3.3V to 5V

AVF

GND

MCU

When R

is removed, the MCU cannot discriminate between an ACS short circuit and

SHUNT

open load failure. See Tab l e 9.

9/13

Application information STCC08

Table 9. STCC08 status truth table with R

SHUNT

removed

IN (MCU generated) AVF MCU DIAGNOSTIC

0 Open collector AC switch OK

0 Open collector to 0 toggle Diode mode

0 0 Short circuit or open lead

10AC switch OK

1 Open collector Open AC switch

STCC08 ZVS application

Figure 9. ZVS application schematic

NEUTRAL

ACS

LINE

POWER SWITCH

SIGNAL SHAPING

GATE DRIVER

AVF DRIVER

3.3V to 5V

ZVS

GND

MCU

The gate driver drives an ACS while the failure detector is used independently for ZVS detection

10/13

STCC08 Package information

4 Package information

● Epoxy meets UL94, V0

In order to meet environmental requirements, ST offers these devices in ECOPACK packages. These packages have a lead-free second level interconnect. The category of second level interconnect is marked on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an ST trademark. ECOPACK specifications are available at

www.st.com.

Table 10. SO-8 dimensions

Dimensions

Seating

Plane

ppp C

Figure 10. Footprint dimensions

in mm(inches)

Ref.

Min. Typ. Max. Min. Typ. Max.

h x 45°

A 1.75 0.069

A1 0.1 0.25 0.004 0.010

A2 1.25 0.049

b 0.28 0.48 0.011 0.019

C 0.17 0.23 0.007 0.009

D 4.80 4.90 5.00 0.189 0.193 0.197

E 5.80 6.00 6.20 0.228 0.236 0.244

E1 3.80 3.90 4.00 0.150 0.154 0.157

e 1.27 0.050

h 0.25 0.50 0.010 0.020

L 0.40 1.27 0.016 0.050

L1 1.04 0.041

k0°8°0°8°

ppp 0.10 0.004

Figure 11. Marking

Millimeters Inches

6.8

(0.268)

4.2

(0.165)

0.6

(0.024)

XXXXX : Marking

XXXXX : Marking ZZ : Manufacturing location

ZZ : Manufacturing location Y : Year

Y : Year WW : week

WW : week

x x x x x x

xx xx xx xx xx xx

z z y w w

zz zz yy ww ww

1.27

(0.050)

Pin 1

11/13

Ordering information STCC08

5 Ordering information

Table 11. Ordering information

Order code Marking Weight Base Qty Delivery Mode

STCC08 STCC08 0.08 g 100 Tube

STCC08RL STCC08 0.08 g 2500 Tape and reel 13”

6 Revision history

Table 12. Document revision history

Date Revision Changes

20-Mar-2008 1 Initial release.

12/13

STCC08

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13/13

ST STCC08 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

1 Characteristics

Figure 1. Circuit block diagram

Table 1. Circuit pin descriptions

Figure 2. Pin layout (top view)

Table 2. Pin allocations

Table 4. Recommended operating conditions

Table 5. Electrical characteristics

Table 6. Thermal resistance

Table 7. System related electromagnetic compatibility ratings

2 Functional description

Figure 4. Failure mode detection for inductive loads in DC control mode

3 Application information

Figure 5. Application example with an MCU direct drive + ACS

3.1 Recommendations

Figure 6. Non-insulated application

Figure 7. ACS benefits

Figure 8. Open load and Short circuit ACS discrimination

Figure 9. ZVS application schematic

4 Package information

Table 10. SO-8 dimensions

Figure 11. Marking

5 Ordering information

Table 11. Ordering information

6 Revision history

Table 12. Document revision history