PTC AS2916B16DT Pwm controller Datasheet

AS2916
PWM Controller
Functional Block Diagram
VREG
VCC
50µA
5V enable
(Bulk OK)
+
BOK
2V5
S
5V Reg
REG
Q
–
+
R
UVLO
•
–
VREG
ON
+
–
2V5
(RUN)
AUX_ON
6µA
SNSB
SS
CMPB
CM PWM
2R
+
–
1V
WBL
VCC
R
(PWM)
OSC
OUTB
+
–
SS PWM
RT/CT
VCC
x1
RAMP
GND
(Blank)
OSC
(Blank)
VCC
gm
CMPA
(PWM)
AUX_ON
x1
–
2R
GND
+
CM PWM
1V
R
SNSA
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OUTA
250
PWM Controller
AS2916
Pin Function Description
Pin Number
Function
Description
1
OUTB
2
VCC
Positive supply for the IC. Absolute maximum rating is 20 V.
The running voltage shall be provided by the Auxiliary conver
tor.
3
REG
Output of 5 V series regulator.
4
SNSB
This is the Main convertor current sense pin. An external RC
filter from the Main power FET and slope compensation resistor from the RAMP pin is all the expected external circuitry.
5
CMPB
This is the Main output control pin. An opto isolated control
signal from the secondary side error amplifier is buffered and
connected to the invert pin of the main output current mode
comparator. A pull-up current of 1 mA is provided so the only
external circuitry expected is a common emitter opto-isolator.
6
SS
This pin provides a 6 µA current source to linearly charge an
external capacitor. This spin is compared to the RAMP pin in
the soft start comparator, terminating output pulses when
RAMP goes above the SS voltage. While this pin is held low,
the main output is inhibited.
7
RAMP
This pin is a level-shifted and buffered oscillator waveform,
used to provide slope compensation for the Main and Auxiliary
converters. The pin also serves as the non-inverting input of
the soft-start comparator.
8
OSC
Oscillator frequency and maximum duty cycle are set by connecting the resistor (RT) to VREG and a capacitor (CT) to
ground.
9
WBL
Provides an FM modulation of the oscillator, approximately
±25% deviation frequency, at a modulation rate set by an external cap at WBL. Shorting to GND eliminates modulation.
10
ON
11
BOK
This is the gate drive output for the Main FET. The totem pole
output has equivalent of an extra 10 Ω resistor to limit the FET
turn on speed and a pull down resistor to ensure the FET gate
is never open. No external circuitry except for the FET is
expected on this pin. The largest FET expected to be driven is
IRFBC40. If a larger power FET is used, a buffer might be
required.
This pin is used to remotely turn the main convertor ON/OFF
either for normal user application or for protection.
Bulk OK. This is a brownout protection feature. The pin monitors the bulk voltage through a resistor divider. When BOK
exceeds 2.5 V a 50 µA current is sourced from the pin for hysteresis. When the pin drops below 2.5 V the hysteresis is
turned off and SS is pulled low,inhibiting the main output.
The Auxiliary output is not tied to BOK and will run as long as
there is sufficient bias voltage.
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251
AS2916
PWM Controller
Pin Function Description
Pin Number
Function
12
CMPA
Description
This is the Auxiliary convertor error amplifier compensation pin
or if secondary controller is desired, the Auxiliary control input
pin. A simple capacitor to ground is the only circuitry expected.
Note: There is no external connection for voltage feedback.
Voltage sensing is provided internally in such a way that VCC
not loaded until it reaches predefined threshold. If secondary
control is required, it can be forced into the CMPA pin.
is
13
SNSA
This is the Auxiliary convertor current sense pin. An external
RC filter from the Auxiliary power FET and slope compensation
resistor from the RAMP pin is all the expected external circuitry.
14
OUTA
This is the gate drive output for the Auxiliary FET. The totem
pole output has equivalent of an extra 33 Ω resistor to limit the
FET turn on speed and a pull down resistor to ensure the FET
gate is never open. No external circuitry except for the FET is
expected on this pin. The largest FET expected to be driven is
IRF820. If a larger power FET is used, a buffer might be
required.
15
GND
Signal ground.
16
PGND
Power ground.
Absolute Maximum Ratings
Parameter
Symbol
Rating
Unit
Reference Current
IREF
200
mA
Output Current
IOUT
1
A
Supply Voltage
VCC
20
V
Output Voltage
VOUT
20
V
Continuous Power
PD
500
mW
Junction Temperature
TJ
150
°C
Storage Temperature
TSTG
–60 to +150
°C
TL
300
°C
Lead Temperature (Soldering, 10 seconds)
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252
PWM Controller
AS2916
Electrical Characteristics
Electrical characteristics are guaranteed over the full junction temperature range (0-105°). Ambient temperature must be derated
based upon power dissipation and package thermal characteristics. The conditions are: VCC = 15 V, BOK = 3 V, ON = 3 V, RT =
680 Ω, CT = 10 nF, and CWBL = 2.2 nF, unless otherwise specified. To override UVLO, VCC should be raised above UVLOHIGH
prior to test.
Parameter
Symbol
Test Condition
Min.
Typ.
Max.
Unit
VREG
PSRR
TJ = 25°C, IREG = 1 mA
12 ≤ VCC ≤ 18 V
4.90
5.00
5.10
V
5
15
mV
5
15
mV
5 V Regulator
Output Voltage
Line Regulation
1.0 ≤ IREG ≤ 20 mA
Load Regulation
Temperature Stability
TCREG
Total Output Variation
Long-Term Stability
Output Noise Voltage
Maximum Source Current
0.2
Line, Load, Temperature
4.85
Over 1,000 hrs at 25°C
5.0
VNOISE
IMAX
10 ≤ f ≤ 100 kHz, TJ = 25°C
VREG = 4.8 V
50
fOSC
TA = 25°C, VWBL = 0 V
8.5 V ≤ VCC ≤ 18V
0.4
mV/°C
5.15
V
25
mV
µV
30
120
180
mA
117
132
143
kHz
0.2
1.0
%
Oscillator
Initial Frequency
Voltage Stability
Temperature Stability
Amplitude
Upper Trip Point
Lower Trip Point
Discharge Current
TCF
VOSC
VH
TMIN ≤ TJ ≤ TMAX
VOSC peak-to-peak
VWBL = 0 V
5
%
1.55
V
2.8
V
VL
IDSC
VWBL = 0 V
1.25
V
Duty Cycle Limit
Over-Temperature Shutdown
VOSC = 3 V
RT = 680 Ω, CT = 10 nF,
TJ = 25°C
7.5
8.7
9.5
mA
46
50
54
%
TOT
140
°C
Wobble Oscillator
Wobble Rate
OSC Frequency Deviation
Amplitude
Upper Trip Point
Lower Trip Point
FWBL
DEV
VWBL
VH
2.2 nF WBL to GND
3.4
4.5
6.0
kHz
Change in main oscillator freq.
+30
+40
+50
kHz
VWBL peak-to-peak
1.8
V
2.7
V
0.9
V
Charge Current
VL
ICHRG
VWBL = 0.7 V
–25
–36
–50
µA
Discharge Current
IDSC
VWBL = 4.8 V
25
36
50
µA
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253
AS2916
PWM Controller
Electrical Characteristics
Electrical characteristics are guaranteed over the full junction temperature range (0-105°). Ambient temperature must be derated
based upon power dissipation and package thermal characteristics. The conditions are: VCC = 15 V, BOK = 3 V, ON = 3 V, RT =
680 Ω, CT = 10 nF, and CWBL = 2.2 nF, unless otherwise specified. To override UVLO, VCC should be raised above UVLOHIGH
prior to test.
Parameter
Symbol
Test Condition
Min.
Typ.
Max.
Unit
VCCREG
Gm
13.4
14.5
15.7
V
1.0
mS
ICMPALow VCC = 16 V, VCMPA = 1.1 V
ICMPAHigh VCC = 12 V, VCMPA = 5 V
VCMPAHigh VCC = 12 V, ICMPA = 0.5 mA
VCMPALow VCC = 16 V, ICMPA = 2 mA
2.0
6.0
mA
–0.5
-1.1
mA
Auxiliary PWM Comparator Input (CMPA)
Regulation Voltage
Transconductance
Output Sink Current
Output Source Current
Output Swing High
Output Swing Low
5.4
5.7
0.2
V
1.1
V
Auxiliary Current Sense Comparator (SNSA)
Transfer Gain
CMPA Level Shift
Current Sense Threshold
Input Bias Current
AVSNSA
VLS
–0.2 ≤ VSNSA ≤ 0.8 V
VSNSA = 0 V
VSNSA
IBIAS
VCMPA = 5 V
3.0
1.5
0.95
Propagation Delay to Output tPD
Main PWM Comparator Input (CMPB)
Comp Source Current
Comp Source Impedance
Comp Source High
ICMPB
VCMPB = 2.5 V
ZCMPB
VCMPBHigh
V/V
1.05
V
1.15
V
–1.0
–10
µA
80
150
ns
–1.0
–1.4
10
15
mA
5.4
5.6
V
–0.2 ≤ VSNSB ≤ 0.8 V
3.0
V/V
VSNSB = 0 V
1.5
V
20
kΩ
Main Current Sense Comparator (SNSB)
Transfer Gain
CMPB Level Shift
AVSNSB
VLS
Current Sense Threshold
VSNSB
IBIAS
Propagation Delay to Output tPD
VCMPB = 5 V
0.95
Input Bias Current
1.05
1.15
V
–1.0
–10
µA
80
150
ns
–6.0
–10
µA
Soft Start Comparator
SS Charge Current
SS Discharge Current
SS Lower Clamp
ICharge SS VSS ≤ VRAMP
IDsc SS
VSS = 1 V, VON <1.5 V
VSS low
Propagation Delay to Output tPB
RAMP High Level
VRAMPH
RAMP Low Level
VRAMPL
RAMP Levels TC
RAMP Sink Current
RAMP Source Current
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TJ = 25°C
TJ = 25°C
–4.0
2.0
2.0
0.45
Note: RAMP waveform is same
as OSC waveform, but level
shifted down one diode drop.
IRAMPL
IRAMPH
TJ = 25°C
TJ = 25°C
254
10
mA
0.05
0.2
V
50
100
ns
2.15
2.3
V
0.6
0.75
V
–2.0
mV/°C
0.1
0.2
mA
–2.0
–10
mA
PWM Comtroller
AS2916
Electrical Characteristics
Electrical characteristics are guaranteed over the full junction temperature range (0-105°). Ambient temperature must be derated
based upon power dissipation and package thermal characteristics. The conditions are: VCC = 15 V, BOK = 3 V, ON = 3 V, RT =
680 Ω, CT = 10 nF, and CWBL = 2.2 nF ,unless otherwise specified. To override UVLO, VCC should be raised above UVLOHIGH
prior to test.
Parameter
Symbol
Test Condition
Min.
Typ.
Max.
Unit
0.1
0.4
V
1.5
2.2
Main Output
Output Low Level
VOUTBL
Output Low Level
Output High Level
VOUTBL
VOUTBH
Output High Level
VOUTBH
ISINK = 10 mA
ISINK = 150 mA
ISOURCE = 10 mA, VCC = 15 V
ISOURCE = 150 mA, VCC = 15V
13
10
10.7
V
10
Ω
On Resistance High
Rise Time
V
12
V
tR
tF
CL = 1.3 nF, 10% to 90%
CL = 1.3 nF, 90% to 10%
50
150
ns
50
150
ns
ZOUT
VCC = 6 V
20
ISINK = 10 mA
ISINK = 150 mA
0.1
0.4
Output Low Level
VOUTBL
VOUTBL
1.5
2.2
Output High Level
VOUTBH
ISOURCE = 10 mA, VCC = 15V,
VCMPA = 5 V
12
13
V
Output High Level
VOUTBH
ISOURCE = 110 mA, VCC = 15V,
VCMPA = 5 V
7
8
V
33
Ω
Fall Time
Output Impedance to GND
in UVLO State
kΩ
Auxiliary Output
Output Low Level
On Resistance High
Rise Time
Fall Time
Output Impedance to GND
in UVLO State
V
V
tR
tF
CL =350 pF, 10% to 90%
CL = 350 pF, 90% to 10%
70
150
ns
50
150
ns
ZOUT
VCC = 6 V
20
kΩ
Under-Voltage Lockout
Start-Up Threshold
VCC(ON)
12.4
13.5
Stop Threshold
VCC(OFF)
ICC
7
7.5
8
V
Start-Up Current
0.1
25
µA
Operating Supply Current
ICC
18
25
mA
VCC = 15 V
14.7
V
Housekeeping
BOK UV Threshold
VBOK UV TJ = 25°C
IHYST BOK VBOK = 2.6 V
IBOK
VBOK = 2.4 V
2.50
2.537
2.575
V
42
50
58
µA
–0.1
–1.0
µA
2.35
2.5
2.65
V
ON Hysteresis
VON
∆VON
–0.7
–0.9
–1.1
V
ON Bias Current
IBIAS ON
–0.5
–10
µA
BOK UV Hysteresis Current
BOK Input Bias Current
ON Threshold
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VON = 2.3 V
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