ETC ACT30AHT

Datasheet
Rev 2, 5/2005
ACT30
ACT30
HIGH PERFORMANCE OFF-LINE CONTROLLER
ActiveSwitcherTM IC Family
FEATURES
GENERAL DESCRIPTION
The ACT30 is a high performance
green-energy offline power supply controller. It
features a scalable driver for driving external
NPN or MOSFET transistors for line voltage
switching. This proprietary architecture enables
many advanced features to be integrated into a
small package (TO-92 or SOT23-5), resulting in
lowest total cost solution.
Lowest Total Cost Solution
0.15W Standby Power
Emitter Drive Allows Safe NPN Flyback Use
Hiccup Mode Short Circuit
Current Mode Operation
Over-Current Protection
Under-voltage Protection with Auto-restart
Proprietary Scalable Output Driver
Flexible Packaging Options (including TO-92)
65kHz or 100kHz Switching Frequency
Selectable 0.4A to 1.2A Current Limit
The ACT30 design has 6 internal terminals
and is a pulse frequency and width modulation IC
with many flexible packaging options. One
combination of internal terminals is packaged in
the space-saving TO-92 package (A/B/C/D
versions) for 65kHz or 100kHz switching
frequency and with 400mA or 800mA current limit.
The E version (SOT23-5) can be configured for
higher current limit.
APPLICATIONS
Battery Chargers
Power Adaptors
Standby Power Supplies
Appliances
Universal Off-line Power Supplies
Consuming only 0.15W in standby, the IC
features over-current, hiccup mode short circuit,
and under-voltage protection mechanisms.
The ACT30 is ideal for use in high
performance universal adaptors and chargers.
For highest performance versus cost and
smallest PCB area, use the ACT30 in
combination with the ACT32 CV/CC Controller.
Figure 1. Simplified Application Circuit
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ACT30
ORDERING INFORMATION
PART NUMBER
SWITCHING FREQUENCY
CURRENT LIMIT
TEMPERATURE RANGE
PACKAGE
PINS
ACT30AHT-A
65kHz
400mA
-40°C to 85°C
TO-92
3
ACT30BHT-A
65kHz
800mA
-40°C to 85°C
TO-92
3
ACT30CHT-A
100kHz
400mA
-40°C to 85°C
TO-92
3
ACT30DHT-A
100kHz
800mA
-40°C to 85°C
TO-92
3
ACT30EUC-T
SELECTABLE
ADJUSTABLE
-40°C to 85°C
SOT23-5
5
PIN CONFIGURATION
ACT30A
ACT30B
ACT30C
ACT30D
1
2
VDD
1
GND
2
FREQ
3
5
DRV1
4
DRV2
ACT30E
3
TO-92
SOT23-5
PIN NAME
PIN DESCRIPTION
PIN DESCRIPTION
PIN NUMBER
TO-92
SOT23-5
1
1
VDD
Power Supply Pin. Connect to optocoupler's emitter. Internally limited to
5.5V max. Bypass to GND with a proper compensation network.
2
2
GND
Ground
DRV
Driver Output (TO-92 Only). Connect to emitter of the high voltage NPN or
MOSFET. For ACT30A/C, DRV pin is internally connected to DRV1. For
ACT30B/D, DRV pin is internally connected to both DRV1 and DRV2.
5
DRV1
Driver Output 1 (SOT23-5 Only). Also used as supply input during startup.
4
DRV2
Driver Output 2 (SOT23-5 Only)
3
FREQ
Frequency Select (SOT23-5 Only). This terminal has an internal 200kΩ pull
down resistor. Connect to VDD for 100kHz operation. Connect to GND or
leave unconnected for 65khz operation.
3
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ACT30
ABSOLUTE MAXIMUM RATINGS
(Note: Do not exceed these limits to prevent damage to the device. Exposure to absolute maximum rating conditions for long
periods may affect device reliability.)
PARAMETER
VALUE
UNIT
-0.3 to 6
V
20
mA
-0.3 to 18
V
Internally limited
A
VDD, FREQ Pin Voltage
VDD Current
DRV, DRV1, DRV2 Voltage
Continuous DRV, DRV1, DRV2 Current
Maximum Power Dissipation
TO-92
0.6
SOT23-5
0.39
W
Operating Junction Temperature
-40 to 150
°C
Storage Temperature
-55 to 150
°C
300
°C
Lead Temperature (Soldering, 10 sec)
ELECTRICAL CHARACTERISTICS
(VDD = 4V, TJ = 25°C unless otherwise specified)
PARAMETER
SYMBOL
TEST CONDITIONS
VDD Start Voltage
VSTART
Rising edge
DRV1 Start Voltage
VDRVST
DRV1 must be higher
than this voltage to
start up.
DRV1 Short-Circuit Detect Threshold
VSCDRV
VDD Under-voltage Threshold
VUV
VDD Clamp Voltage
Startup Supply Current
IDDST
MIN
TYP
MAX
UNIT
4.75
5
5.25
V
ACT30A/C
8.6
10.5
ACT30B/D
9.6
11.5
6.8
V
V
Falling edge
3.17
3.35
3.53
V
10mA
5.15
5.45
5.75
V
0.23
0.45
mA
0.7
1
mA
VDD = 4V before VUV
Supply Current
IDD
Switching Frequency
fSW
Maximum Duty Cycle
DMAX
Minimum Duty Cycle
DMIN
VDD = 4.6V
3.5
ILIM
ACT30A/C
VDD = VUV +
ACT30B/D; ACT30E
0.1V
with DRV1 = DRV2
400
Effective Current Limit
ACT30A/B or FREQ = 0
55
65
85
ACT30C/D or FREQ = VDD
75
100
125
ACT30A/C, VDD = 4V
67
75
83
ACT30B/D, VDD = 4V
60
kHz
%
%
mA
800
VDD to DRV1 Current Coefficient
GGAIN
-0.29
A/V
VDD Dynamic Impedance
RVDD
9
kΩ
IDRV1 = IDRV2 = 0.05A
3.6
Ω
DRV1 Rise Time
1nF load, 15Ω pull-up
30
ns
DRV1 Fall Time
1nF load, 15Ω pull-up
20
ns
DRV1 and DRV2 Switch Off Current
Driver off, VDRV1 = VDRV2 = 10V
12
DRV1 or DRV2 Driver On-Resistance
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30
µA
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ACT30
STARTUP SEQUENCE
FUNCTIONAL DESCRIPTION
Figure 1 shows a Simplified Application
Circuit for the ACT30. Initially, the small current
through resistor R1 charges up the capacitor C1,
and the BJT acts as a follower to bring up the
DRV1 voltage. An internal regulator generates a
VDD voltage equal to VDRV1 – 3.6V for ACT30A/C
(VDRV1 – 4.6V for ACT30B/D) but limits it to 5.5V
max. As VDD crosses 5V, the regulator sourcing
function stops and VDD begins to drop due to its
current consumption. As VDD voltage decreases
below 4.75V, the IC starts to operate with
increasing driver current. When the output
voltage reaches regulation point, the optocoupler
feedback circuit stops VDD from decreasing
further. The switching action also allows the
auxiliary windings to take over in supplying the
C1 capacitor. Figure 3 shows a typical startup
sequence for the ACT30.
Figure 2 shows the Functional Block Diagram
of the ACT30. The main components include
switching
control
logic,
two
on-chip
medium-voltage power-MOSFETs with parallel
current sensor, driver, oscillator and ramp
generator, current limit VC generator, error
comparator,
hiccup
control,
bias
and
undervoltage-lockout, and regulator circuitry.
As seen in Figure 2, the design has 6 internal
terminals. VDD is the power supply terminal.
DRV1 and DRV2 are linear driver outputs that
can drive the emitter of an external high voltage
NPN transistor or N-channel MOSFET. This
emitter-drive method takes advantage of the high
VCBO of the transitor, allowing a low cost
transistor such as ‘13003 (VCBO = 700V) or
‘13002 (VCBO = 600V) to be used for a wide AC
input range. The slew-rate limited driver coupled
with the turn-off characteristics of an external
NPN result in lower EMI.
To limit the auxiliary voltage, use a 12V zener
diode for ACT30A/C or a 13V zener for
ACT30B/D (D1 diode in Figure 1).
The driver peak current is designed to have a
negative voltage coefficient with respect to
supply voltage VDD, so that lower supply voltage
automatically results in higher DRV1 peak
current. This way, the optocoupler can control
VDD directly to affect driver current.
Even though up to 2MΩ startup resistor (R1)
can be used due to the very low startup current,
the actual R1 value should be chosen as a
compromise between standby power and startup
time delay.
DRV1
− +
REGULATOR
VDD
9k
DRV2 ‡
3.6V (ACT30A/C)
4.6V (ACT30B/D)
BIAS
& UVLO
HICCUP
CONTROL
OSC &
RAMP
CURRENT
FREQ †
PFWM
SWITCHING
CONTROL
LOGIC
SLEW
1x
200k
56x
56x
20k
ERROR
COMP
ILIM VC
GENERATOR
4.75V
−
+
+
−
40
20k
10uA/V
GND
†
‡
GND
FREQ terminal wire-bonded to VDD in ACT30C/D (TO-92)
DRV2 terminal wire-bonded to DRV1 in ACT30B/D (TO-92)
Figure 2. Functional Block Diagram
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ACT30
VAC
pulse-skipped
VDRVST
VDRV1
5V
VDD
IPRIMARY
VOUT
Figure 3. Startup Waveforms
NORMAL OPERATION
CURRENT LIMIT ADJUSTMENT
In normal operation, the feedback signal from
the secondary side is transmitted through the
optocoupler as a current signal into VDD pin,
which has dynamic impedance of 9kΩ. The
resulting VDD voltage affects the switching of the
IC. As seen from the Functional Block Diagram,
the Current Limit VC Generator uses the VDD
voltage difference with 4.75V to generate a
proportional offset at the negative input of the
Error Comparator.
The IC's proprietary driver arrangement
allows the current limit to be easily adjusted
between 400mA and 1.2A. To understand this,
the drivers have to be utilized as linear resistive
devices with typically 3.6Ω (rather than as digital
output switches). The current limit can then be
calculated through linear combination as shown
in Figure 4. For TO-92 package, the ACT30A/C
are preprogrammed to 400mA current limit and
The drivers turn on at the beginning of each
switching cycle. The current sense resistor
current, which is a fraction of the transformer
primary current, increases with time as the
primary current increases. When the voltage
accross this current sense resistor plus the
oscillator ramp signal equals Error Comparator's
negative input voltage, the drivers turn off. Thus,
the peak DRV1 current has a negative voltage
coefficent of -0.29A/V and can be calculated
from the following:
DRV1
IDRV1PEAK = 0.29A/V • (4.75V – VDD)
DRV2
ILIM = 400 mA
DRV2
DRV1
DRV2
RD
 7.2Ω + RD 

ILIM = 400 mA • 

 3.6Ω + RD 
DRV1
ILIM = 800 mA
for VDD < 4.75V and duty cycle < 50%.
When the output voltage is lower than
regulation, the current into VDD pin is zero and
VDD voltage decreases. At VDD = VUV = 3.35V, the
peak DRV1 current has maximum value of
400mA.
RD
DRV1
DRV2
R 

ILIM = 400mA •  2 + D 
3
.6Ω 

Figure 4. Driver Output Configurations
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ACT30
the ACT30B/D are preprogrammed to 800mA
current limit. For ACT30E (SOT23-5) packages,
both DRV1 and DRV2 terminals are provided.
SHORT CIRCUIT HICCUP
When the output is short circuited, the ACT30
enters hiccup mode operation. In this condition,
the auxiliary supply voltage collapses. An on-chip
detector compares DRV1 voltage during the
off-time of each cycle to 6.8V. If DRV1 voltage is
below 6.8V, the IC will not start the next cycle,
causing both the auxiliary supply voltage and VDD
to reduce further. The circuit enters startup mode
when VDD drops below 3.35V. This hiccup
behaviour continues until the short circuit is
removed. In this behavior, the effective duty
cycle is very low resulting in very low short circuit
current.
PULSE SKIPPING
The PFWM Switching Control Logic block
operates in different modes depending on the
output load current level. At light load, the VDD
voltage is around 4.75V. The energy delivered by
each switching cycle (with minimum on time of
500ns) to the output causes VDD to increase
slightly above 4.75V. The FPWM Switching
Control Logic block is able to detect this
condition and prevents the IC from switching until
VDD is below 4.75V again. This results in a
pulse-skipping action with fixed pulse width and
varying frequency, and low power consumption
because the switching frequency is reduced.
Typical system standby power consumption is
0.15W.
To make sure that the IC enters hiccup mode
easily, the transformer should be constructed so
that there is close coupling between secondary
and auxiliary, so that the auxiliary voltage is low
when the output is short-circuited. This can be
achieved with the primary/auxiliary/secondary
sequencing from the bobbin.
APPLICATION INFORMATION
IC
EXTERNAL POWER TRANSISTOR
The ACT30 allows a low-cost high voltage
power NPN transistor such as ‘13003 or ‘13002
to be used safely in flyback configuration. The
required collector voltage rating for VAC = 265V
with full output load is at least 600V to 700V. As
seen from Figure 5, NPN Reverse Bias Safe
Operation Area, the breakdown voltage of an
NPN is significantly improved when it is driven at
its emitter. Thus, the ACT30+’13002 or ‘13003
combination meet the necessary breakdown
safety requirement even though RCC circuits
using ‘13002 or ‘13003 do not. Table 1 lists the
breakdown voltage of some transistors
appropriate for use with the ACT30.
Base-Drive
Safe
Region
(RCC)
VCEO
VCBO
VCEO
IC
MJE13002
600V
300V
1.5A
8
TO-126
MJE13003,
KSE13003
700V
400V
1.5A
8
TO-126
STX13003
700V
400V
1A
8
TO-92
Active-Semi, Inc.
VCBO
VC
Figure 5. NPN Reverse Bias Safe Operation Area
The power dissipated in the NPN transistor is
equal to the collector current times the
collector-emitter voltage. As a result, the
transistor must always be in saturation when
turned on to prevent excessive power dissipation.
Select an NPN transistor with sufficiently high
current gain (hFEMIN > 8) and a base drive resistor
(R2 in Figure 1) low enough to ensure that the
transistor easily saturates.
Table 1. Recommended Power Transistors List
DEVICE
EmitterDrive Safe
Region
(ACT30)
hFEMIN PACKAGE
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ACT30
Figure 6. A 3.75W Charger Using ACT30A in combination with ACT32
APPLICATION EXAMPLE
LAYOUT CONSIDERATIONS
The application circuit in Figure 6 provides a
5V/0.75A constant voltage/constant current
output. An ACT30A is used in combination with
the ACT32 for highest efficiency and lowest
component count.
The following should be observed when doing
layout for the ACT30:
1. Use a "star point" connection at the GND pin
of ACT30 for the VDD bypass components (C5
and C6 in Figure 6), the input filter capacitor (C2
in Figure 6) and other ground connections on the
primary side.
To change the constant output voltage VOUTCV
and constant current limit IOUTCC, modify R7 and
R6 as following:
R6 = 250mV/IOUTCC
2. Keep the loop across the input filter capacitor,
the transformer primary windings, and the high
voltage transistor, and the ACT30 as small as
possible.
The performance of this circuit is summarized
in Table 2.
3. Keep ACT30 pins and the high voltage
transistor pins as short as possible.
R7 = 80kΩ • [(VOUTCV - 1V)/3.8V - 1]
Table 2. System Performance of Circuit in Figure 6
110VAC
220VAC
Standby Power
0.09W
0.15W
Current Limit
0.75A
0.75A
Full Load Efficiency
65%
67%
Active-Semi, Inc.
4. Keep the loop across the secondary windings,
the output diode, and the output capacitors as
small as possible.
5. Allow enough copper area under the high
voltage transistor, output diode, and current
shunt resistor for heat sink.
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ACT30
PACKAGE OUTLINE
TO-92 PACKAGE OUTLINE AND DIMENSIONS (AMMO TAPE PACKING)
DIMENSION IN
MILIMETERS
DIMENSION IN
INCHES
MIN
MAX
MIN
MAX
A
3.300
3.700
0.130
0.146
A1
1.100
1.400
0.043
b
0.380
0.550
c
0.360
D
4.400
D1
3.430
E
4.300
SYMBOL
e
e1
DIMENSION IN
INCHES
MIN
MAX
MIN
MAX
∆k
-1.0
1.0
-0.039
0.039
0.055
F1, F2
2.2
2.8
0.087
0.110
0.015
0.022
H
19
21
0.748
0.827
0.510
0.014
0.020
H0
15.5
16.5
0.610
0.650
4.700
0.173
0.185
L1
2.5
P
12.4
13.0
0.488
0.512
∆P
-1.0
1.0
-0.039
0.039
P0
12.5
12.9
0.492
0.508
0.104
P1
3.55
4.15
0.140
0.163
0.063
P2
6.05
6.65
0.238
0.262
0.015
Q1
3.8
4.2
0.150
0.165
t1
0.35
0.45
0.014
0.018
t2
0.15
0.25
0.006
0.010
W
17.5
19
0.689
0.748
W0
5.5
6.5
0.217
0.256
W1
8.5
9.5
0.335
0.374
0.135
4.700
1.270 TYP
2.440
Φ
h
DIMENSION IN
MILIMETERS
2.640
0.169
0.380
0.185
0.050 TYP
0.096
1.600
0.000
SYMBOL
0.000
W2
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0.098
1.0
0.039
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ACT30
SOT23-5 PACKAGE OUTLINE AND DIMENSIONS
SYMBOL
DIMENSION IN
MILIMETERS
DIMENSION IN
INCHES
MIN
MAX
MIN
MAX
A
1.050
1.250
0.041
0.049
A1
0.000
0.100
0.000
0.004
A2
1.050
1.150
0.041
0.045
b
0.300
0.400
0.012
0.016
c
0.100
0.200
0.004
0.008
D
2.820
3.020
0.111
0.119
E
1.500
1.700
0.059
0.067
E1
2.650
2.950
0.104
0.116
e
e1
L
0.950 TYP
1.800
0.037 TYP
2.000
0.700 REF
0.071
0.079
0.028 REF
L1
0.300
0.600
0.012
0.024
θ
0°
8°
0°
8°
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make sure that it is suitable for their applications. Active-Semi products are not intended or authorized for use as critical
components in life-support devices or systems. Active-Semi, Inc. does not assume any liability arising out of the use of any
product or circuit described in this datasheet, nor does it convey any patent license.
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