T2117
Zero-Voltage Switch with Adjustable Ramp
Description
The integrated circuit, T2117, is designed as a zero-
voltage switch in bipolar technology. It is used to control
resistive loads at mains by a triac in zero-crossing mode.
A ramp generator allows power control function by
period group control, whereas full-wave logic guarantees
that full mains cycles are used for load switching.
Features
D
Direct supply from the mains
D
Current consumption
≤
0.5 mA
D
Very few external components
D
Full-wave drive – no DC current component in the
load circuit
D
Negative output current pulse typ. 100 mA –
short-circuit protected
D
Simple power control
D
Ramp generator
D
Reference voltage
Applications
D
Full-wave power control
D
Temperature regulation
D
Power blinking switch
Block Diagram
D
1
220 kW
(250 V~)
R
2
(R
sync
)
R
1
BYT41M
18 kW/
2W
–V
S
2
1
R
5
12 kW
max
100 kW
min
R
6
18 kW
N
Reference voltage
1.4 V
3
4
+
+
– Comparator
6
Full-wave logic
Pulse
amplifier
R
3
Ramp
generator
8
Synchronization
5
7
Supply
GND
C
1
100
mF/
16 V
TIC
236N
100
W
V
M
=
230 V~
MT2
MT1
Load
1000 W
L
C
2
2.2
mF/
10 V
R
4
100 kW
T2117
Figure 1. Block diagram with typical circuit, period group control 0 to 100%
Ordering Information
Extended Type Number
T2117-3AS
T2117-TAS
T2117-TAQ
Package
DIP8
SO8
SO8
Tube
Tube
Taped and reeled
Remarks
Rev. A2, 17-Dec-01
1 (11)
T2117
Pin Description
Ramp
C
Ramp
POSIN
NEGIN
1
2
T2117
3
4
6
5
Figure 2. Pinning
8
7
V
sync
GND
1
Output
R
4
V
S
–V
S
2
T2117
Ramp
control
C
2
Figure 3. Pin 1 internal network
Pin
1
2
3
4
5
6
7
8
Symbol
Ramp
C
Ramp
POSIN
NEGIN
V
S
Output
GND
V
sync
Function
Ramp output
Ramp capacitor
Non-inverting comparator input
Inverting comparator input
Supply voltage
Trigger pulse output
Ground
Voltage synchronization
Figure 4. Threshold voltage of the ramp at V
S
= –8.8 V
t
V
1
–1.6 V
Final voltage
V
min
Initial voltage
V
max
–7.6 V
T
General Description
The integrated circuit T2117 is a triac controller for zero-
crossing mode. It is designed to control power in
switching resistive loads of mains supplies.
Information regarding supply sync. is provided at Pin 8
via resistor R
Sync
. To avoid DC load on the mains, the full-
wave logic guarantees that complete mains cycles are
used for load switching.
A fire pulse is released when the inverting input of the
comparator is negative (Pin 4) with respect to the non-
inverting input (Pin 3) and internal reference voltage. A
ramp generator with free selectable duration can be
performed by capacitor C
2
at Pin 2. The ramp function is
used for open-loop control (figure 4), but also for applica-
tion with proportional band regulation (figure 11). Ramp
voltage available at capacitor C
2
is decoupled across the
emitter follower at Pin l. To maintain the lamp flicker
specification, ramp duration is adjusted according to the
controlling load. In practice, interference should be
avoided (temperature control). Therefore, a two-point
control is preferred to proportional control. One can use
internal reference voltage for simple applications. In that
case, Pin 3 is inactive and connected to Pin 7 (GND), see
figure 13.
Triac Firing Current (Pulse)
This depends on the triac requirement. It can be limited
with gate series resistance which is calculated as follows:
R
Gmax
7.5 V – V
Gmax
– 36
W
I
Gmax
I
P
=
I
Gmax
T
t
p
where:
V
G
= Gate voltage
I
Gmax
= Maximum gate current
I
p
= Average gate current
t
p
= Firing pulse width
T
= Mains period duration
Firing Pulse Width t
p
(Figure 5)
This depends on the latching current of the triac and its
load current. The firing pulse width is determined by the
zero-crossing detection which can be influenced with the
help of sync. resistance, R
sync
, (figure 6).
t
p
=
2
w
arc. sin
I
L
V
M
P 2
2 (11)
Rev. A2, 17-Dec-01
T2117
whereby:
=
I
L
V
M
=
P
=
Latching current of the triac
Mains supply, effective
Power load (user’s power)
The series resistance R
1
can be calculated (figures 7
and 8) as follows:
V
Mmin –
V
Smax
R
1max
= 0.85
; P
(R1)
=
2 I
tot
I
tot
= I
S
+ I
P
+ I
x
(V
M –
V
S
)
2
2 R
1
Total current consumption is influenced by the firing
pulse width which can be calculated as follows:
R
sync
+
V
M
2 sin (w
2
)
*
0.6 V
*
49 kW
3.5
10
*
5
A
tp
10.00
V
Mains
= 230 V∼
1.00
t p ( ms )
whereby:
V
M
= Mains voltage
V
S
= Limiting voltage of the IC
I
tot
= Total current consumption
I
S
= Current requirement of the IC (without load)
I
x
= Current requirement of other peripheral
components
P
(R1)
= Power dissipation at R
1
50
0.10
I
L
( mA)
200
40
V
Mains
=230VX
R
1
( k
W
)
30
100
0.01
10
50
100
1000
P(W)
10000
20
10
0
Figure 5. Output pulse width
2000
V
Mains
= 230 V∼
1600
Rsync ( kOhm )
1200
0
3
6
9
12
15
I
tot
( mA )
Figure 7. Maximum resistance of R
1
6
800
5
400
0
0
200
400
600
800 1000 1200 1400
tp (
ms
)
P
R1
( W )
4
3
2
1
0
0
3
6
9
12
15
I
tot
( mA )
V
Mains
=230VX
Figure 6. Synchronization resistance
Supply Voltage
The T2117 contains voltage limiting and can be con-
nected with the mains supply via the diode D
1
and the
resistor R
1
. Supply voltage between Pin 5 and 7 is limited
to a typical value of 9.5 V.
Figure 8. Power dissipation of R
1
according to current consumption
Rev. A2, 17-Dec-01
3 (11)
T2117
Absolute Maximum Ratings
Parameter
Supply current
Sync. current
Output current ramp generator
Input voltages
Pin 5
Pin 8
Pin 1
Pin 1, 3, 4, 6
Pin 2
Pin 8
T
amb
= 45°C
b
T
amb
= 100°C
Junction temperature
Operating ambient temperature range
Storage temperature range
Symbol
–I
S
I
Sync.
I
O
–V
I
–V
I
±V
I
P
tot
P
tot
T
j
T
amb
T
stg
Value
30
5
3
≤V
S
2 to V
S
≤
7.3
400
125
125
0 to 100
–40 to + 125
Unit
mA
mA
mA
V
V
V
mW
mW
°C
°C
°C
Power dissipation
Thermal Resistance
Parameter
Junction ambient
Junction ambient
SO8
DIP8
Symbol
R
thJA
R
thJA
Value
200
110
Unit
K/W
K/W
Electrical Characteristics
–V
S
= 8.8 V, T
amb
= 25°C, reference point Pin 7, unless otherwise specified
Parameter
Supply-voltage limitation
Supply current
Voltage limitation
Synchronization current
Zero detector
Output pulse width
V
M
= 230 V,
R
sync
= 220 kW
R
sync
= 470 kW
V
6
= 0 V
I
8
=
±
1 mA
Test Conditions / Pins
–I
S
= 1 mA
–I
S
= 10 mA
Pin 5
Pin 5
Pin 5
Pin 8
Pin 8
Pin 8
Pin 6
Pin 6
Pin 6
Symbol
–V
S
–V
S
–I
S
±
V
I
±I
sync
±I
sync
t
P
t
P
–I
O
±
V
I0
I
IB
–V
IC
–V
Ref
1
1.4
100
7.7
0.12
35
260
460
8.2
Min.
9.0
9.1
Typ.
9.5
9.6
Max.
10.0
10.1
500
8.7
Unit
V
V
mA
V
mA
mA
ms
ms
mA
Output pulse current
Comparator
Input offset voltage
Input bias current
Common-mode input
voltage
Threshold internal
reference
Pin 3,4
Pin 4
Pin 3,4
V
3
= 0 V
Pin 4
15
1
(V
S
–1)
mV
mA
V
V
4 (11)
Rev. A2, 17-Dec-01
T2117
Electrical Characteristics (continued)
–V
S
= 8.8 V, T
amb
= 25°C, reference point Pin 7, unless otherwise specified
Parameter
Ramp generator,
figure 1
Period
–I
S
= 1 mA, i
sync
=1 mA,
C
1
= 100
mF,
C
2
= 2.2
mF,
R
4
= 100 kW
Pin 1
Pin 1
Pin 1
V
2
= –V
S
, I
8
= –1 mA, Pin 2
Test Conditions / Pins
Symbol
Min.
Typ.
Max.
Unit
T
–V
1
–V
1
–I
2
1.2
7.2
14
1.5
1.6
7.6
20
2.0
8.0
26
s
V
V
mA
Final voltage
Initial voltage
Charge current
Applications
L
0.5 ...
2.2 kW
V
M
= 230 V ~
100 nF/
250 V ~
270 kW
BYT41M
18 kW/
1.5 W
56
W
N
82
W
8
7
6
5
T2117
1
150 kW
47
mF/
16V
2
3
4
110 kW
0.47
mF/
10 V
Figure 9. Power blinking switch with f
2.7 Hz, duty cycle 1:1, power range 0.5 to 2.2 kW
Rev. A2, 17-Dec-01
5 (11)
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