TI TPS22946YZPR

TPS22946
www.ti.com
SLVS984A – SEPTEMBER 2009 – REVISED FEBRUARY 2010
ULTRA-LOW POWER, LOW INPUT VOLTAGE, CURRENT-LIMITED LOAD SWITCH
WITH SHUT-OFF, AUTO-RESTART, AND OVER-CURRENT CONDITION TIME-OUT
Check for Samples: TPS22946
FEATURES
1
•
•
•
•
•
•
•
•
•
•
DESCRIPTION
Ultra-Low Quiescent Current 1 mA (typ)
at VIN = 1.8 V
Input Voltage Range: 1.62 V to 5.5 V
Low ON-Resistance
– rON = 300 mΩ at VIN = 5.5 V
– rON = 400 mΩ at VIN = 3.3 V
– rON = 500 mΩ at VIN = 2.5 V
– rON = 600 mΩ at VIN = 1.8 V
Selectable Minimum Current Limit:
155 mA, 70 mA, or 30 mA
Integrated Inrush Current Timeout (8 ms)
Shutdown Current: < 1 mA
Thermal Shutdown
Fault Blanking
Auto Restart
Over-Current Condition Timeout (Automatic
Disable for Permanent Over-Current)
1.8-V Compatible Control Input
ESD Performance Tested Per JESD 22
– 6000-V Human-Body Model
(A114-B, Class II)
Tiny WCSP Package 1.4mm x 0.9 mm (YZP)
The TPS22946 is an ultra-low power load switch that
provides protection to systems and loads in
high-current conditions. The device contains a
300-mΩ current-limited P-channel MOSFET that can
operate over an input voltage range of 1.62 V to
5.5 V. The switch is controlled by an on/off input
(ON), which is capable of interfacing directly with
low-voltage control signals. The TPS22946 includes
thermal shutdown protection that prevents damage to
the device when a continuous over-current condition
causes excessive heating by turning off the switch.
When the switch current reaches the maximum limit,
the TPS22946 operates in a constant-current mode to
prohibit excessive currents from causing damage.
The current limit can be selected using the CL input:
a high CL input sets the current limit to 155 mA, a low
CL input sets the current limit to 70 mA, and a
floating CL input sets the current limit to 30 mA.
APPLICATIONS
If the constant current condition still persists after 10
ms, the switch is turned off and the fault signal pin
(OC) is pulled low. The TPS22946 has an
auto-restart feature which turns the switch on again
after 70 ms if the ON pin is still active. If the
TPS22946 remains in an over-current condition for 5
seconds, the device shuts off until it is turned back on
by setting the ON control signal off and then on
again.
•
•
•
•
•
•
If the device is used to protect an LDO, the inrush
current required by the LDO at startup can, in some
cases, exceed the current limit and initiate a blanking
(current limiting) condition. TPS22946 provides
allowance for this scenario during startup of the LDO
by temporarily increasing the current limit to 435-mA
for 8-ms after the load switch is enabled.
•
•
•
Fingerprint Module Protection
Portable Consumer Electronics
Mobile Phones
Smartphone
Notebooks
GPS Devices
The TPS22946 is available in space-saving
6-terminal WCSP (YZP) package. It is characterized
for operation over the free-air temperature range of
–40°C to 85°C.
Table 1. FEATURE LIST
TPS22946
rON (TYP) AT
5.5 V
300 mΩ
CURRENT LIMIT
INTEGRATED
INRUSH
CURRENT
TIMEOUT
CURRENT
LIMIT
BLANKING
TIME
AUTORESTART
TIME
OVERCURRENT
TIMEOUT
ENABLE
30 mA, 70 mA, or 155 mA
Yes
10 ms
70 ms
6s
Active high
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2009–2010, Texas Instruments Incorporated
TPS22946
SLVS984A – SEPTEMBER 2009 – REVISED FEBRUARY 2010
www.ti.com
ORDERING INFORMATION (1)
PACKAGE (2)
TA
–40°C to 85°C
(1)
(2)
(3)
ORDERABLE PART NUMBER
WCSP – YZP (0.5-mm pitch)
Reel of 3000
TPS22946YZPR
TOP-SIDE MARKING (3)
__5H_
For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI
web site at www.ti.com.
Package drawings, thermal data, and symbolization are available at www.ti.com/packaging.
The actual top-side marking has two preceding characters to denote year, month and one following character to designate the wafer
fab/assembly site. Pin 1 identifier indicates solder-bump composition (1 = SnPb, • = Pb-free).
YZP PACKAGE
TERMINALS ASSIGNMENTS
C
C
C
ON
OC
B
B
B
CL
GND
A
A
A
VIN
VOUT
2
1
2 1
Laser Marking View
1 2
Bump View
TERMINAL FUNCTIONS
TERMINAL
NO.
2
NAME
TYPE
DESCRIPTION
A1
VOUT
O
Output of the power switch
B1
GND
–
Ground
C1
OC
O
Over-current output flag. Active-low open-drain output that indicates an over-current, supply
under-voltage, or over-temperature state.
C2
ON
I
On/off control input
B2
CL
I
Current limit selection. CL high is 155-mA current limit, CL low is 70-mA current limit, and CL floating is
30-mA current limit.
A2
VIN
I
Supply. Input to the power switch and the supply voltage for the device
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Functional Block Diagram
A2
VIN
B2
CL
ON
HardShort
Detection
C2
Control
Logic
Current
Limit
A1
VOUT
Thermal
Shutdown
Oscillator
C1
OC
B1
GND
Table 2. FUNCTION TABLE
ON
CL
TPS22946
L
x
VIN to VOUT switch is off (open)
H
x
VIN to VOUT switch is on (closed)
x
H (1)
Current limit set to 155 mA
x
L (1)
Current limit set to 70 mA
x
(1)
(2)
Float
(2)
Current limit set to 30 mA
Resistance to VCC or GND < 100 Ω
Load on CL: C < 100 pF, R > 10 MΩ
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TPS22946
SLVS984A – SEPTEMBER 2009 – REVISED FEBRUARY 2010
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VIN = L
Reset
VIN = H
ON = L (default)
Yes
Inrush current
solution for 8 ms
ON: L ® H
No
No
ON = H
Yes
Moderate over-current
detection every
63.5 ms for 0.5 ms
(See moderate over-current
flow for details)
Over-temperature
detection every
7.5 ms for 0.5 ms
(See over-temperature
detection flow for details)
Hard-short detection every
0.125 ms for 0.125 ms
(See hard-short flow
for details)
Figure 1. Functional Flow Diagram
4
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SLVS984A – SEPTEMBER 2009 – REVISED FEBRUARY 2010
- Common to all the detection schemes
VIN = L
- Common to OC and HS mode only
Reset
If at any time ON: H → L, then
switch returns to this state
D
VIN = H
ON = L (Default)
C
ON = H
No
Yes
Switch = Open
OC signal = L
Switch = Closed
Switch = Closed
Wait for 63.5mS
AutoRestart = Wait for
70 ms
Yes
ON: L → H
No
ON = H
Moderate OC detect
No
ON = 0.5 ms
Reset
Yes
tTIMEOUT_5S
No
A
No
ON = L
Switch = Open
OC signal = H
OC limit =
H
Current limit = 600 mA
Start tTIMEOUT_600mA = 8 ms
Yes
Start tTIMEOUT_5S
OC limit =
H
Reset
tTIMEOUT_5S
Yes
tTIMEOUT_5S =
6S
No
Yes
ON = H
Switch = Open
OC signal = L
B
No
No
tTIMEOUT_600mA
= 8 ms
Current is limited.
Thermal circuit
is enabled.
Yes
Blanking = Wait for
10 ms
Set current limit back
to default *
No
* Default: As determined by CL
OC – Over current
HS – Hard short
Reset
tTIMEOUT_5S
Yes
OC limit =
H
Figure 2. Moderate Over-Current Detection Flow Diagram
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SLVS984A – SEPTEMBER 2009 – REVISED FEBRUARY 2010
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- Common to all the detection schemes
VIN = L
- Common to OC and HS mode only
Reset
VIN = H
ON = L (Default)
D
If at any time ON: H → L, then
switch returns to this state
C
No
ON = H
Yes
Switch = Closed
A
Yes
ON =
Edge
No
OTD ON = 0.5 ms
Switch = Closed
Wait for 7.5 ms
No
Temp >
140°C
Yes
ON = H
Switch = Open
OC signal = L
No
Temp <
130°C
Yes
Yes
ON = H
No
OTD – Over Temperature Detect
OC – Over Current
HS – Hard Short
ON = L
Switch = Open
OC signal = H
Figure 3. Over-Temperature Detection Flow Diagram
6
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SLVS984A – SEPTEMBER 2009 – REVISED FEBRUARY 2010
- Common to all the detection schemes
VIN = L
- Common to OC and HS mode only
Reset
VIN = H
ON = L (Default)
If at any time ON: H → L, then
switch returns to this state
D
C
No
ON = H
Yes
Switch = Open
OC signal = L
Switch = Closed
Switch = Closed
Wait for 0.125mS
A
AutoRestart = Wait for
70 mS
Yes
ON =
Edge
No
ON = H
Hard Short detect ON
No
= 0.125mS
Yes
No
No
Reset
ON = L
Switch = Open
OC signal = H
HS signal
=H
tTIMEOUT_5S
Yes
Start tTIMEOUT_5S
Reset
tTIMEOUT_5S
Yes
tTIMEOUT_5S =
6S
B
ON = H
Switch = Open
OC signal = L
No
Current is limited.
Thermal circuit is
enabled.
Blanking = Wait for
10mS
Yes
HS signal
=H
OC – Over Current
HS – Hard Short
No
Reset
tTIMEOUT_5S
Figure 4. Hard Short-Circuit Detection Flow Diagram
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SLVS984A – SEPTEMBER 2009 – REVISED FEBRUARY 2010
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ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range (unless otherwise noted)
VI
Input voltage
TJ
Operating junction temperature range
VIN, VOUT, ON, CL
Tstg
Storage temperature range
ESD
Electrostatic discharge protection
–0.3 V to 6 V
–40°C to 125°C
–65°C to 150°C
Human-body model (HBM)
6000 V
DISSIPATION RATINGS (1)
BOARD
PACKAGE
RqJC
RqJA
DERATING FACTOR
ABOVE TA = 25°C
TA < 25°C
TA = 70°C
TA = 85°C
High-K(1)
YZP
17.6°C/W
123.36°C/W
-8.1063 mW/°C
810.63 mW
445.84 mW
324.25 mW
(1)
The JEDEC high-K (2s2p) board used to derive this data was a 3-in x 3-in, multilayer board with 1-ounce internal power and ground
planes and 2-ounce copper traces on top and bottom of the board.
RECOMMENDED OPERATING CONDITIONS
over operating free-air temperature range (unless otherwise noted)
VIN
Input voltage
VON
ON pin voltage
VCL
CL pin voltage
VOUT
OUT pin voltage
TA
Ambient free-air temperature
tCLSET
CL pin setting time
CIN
Input capacitor
VIH
ON low-level input voltage
MIN
MAX
1.62
5.5
UNIT
V
0
5.5
V
0
VIN
V
0
VIN
V
-40
85
°C
8
ms
1 (1)
mF
VIN = 1.8 V
1.1
5.5
VIN = 2.5 V
1.2
5.5
VIN = 3.3 V
1.3
5.5
VIN = 5.5 V
1.4
5.5
VIN = 1.8 V
0.4
VIN = 2.5 V
0.4
VIN = 3.3 V
0.5
V
VIL
ON high-level input voltage
VIH
CL low-level input voltage
VIN = 1.62 V to 5.5 V, IIH = 55 mA
0.7 VIN
VIN
V
VIL
CL high-level input voltage
VIN = 1.62 V to 5.5 V, IIL = 55 mA
GND
0.3 VIN
V
VIN = 5.5 V
(1)
8
V
0.6
See the Application Information section of this data sheet.
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ELECTRICAL CHARACTERISTICS
VIN = 1.62 V to 5.5 V, TYP values at TA = 25°C (unless otherwise noted)
PARAMETER
TEST CONDITIONS
IOUT = 0 mA, VIN = 4.5 V to 5.5 V
IIN
Average quiescent current
TA
(1)
MIN
Full range
IOUT = 0 mA, VIN = 3.0 V to 3.6 V
IOUT = 0 mA, VIN = 1.62 V to 1.98 V
IIN(OFF)
IOUT(LEAKAGE)
OFF state supply current
OFF state switch current
ILIM
Current limit
Ilimit_inrush
Inrush current limit
mA
1
mA
VON = 0 V
Full range
0.1
1.1
mA
25°C
0.3
IOUT = -100 mA
VIN = 2.5 V
Full range
0.4
0.45
25°C
0.4
Full range
0.5
0.55
25°C
0.5
Full range
0.6
0.65
25°C
0.6
Full range
0.8
0.7
Full range
0.9
1
VON = VIN or GND
Full range
VIN = 1.8 V, VOUT = 1.5 V, CL = GND
Full range
VIN = 3.3 V, VOUT = 3.0 V, CL = GND
Full range
VIN = 1.8 V, VOUT = 1.5 V, CL = VIN
Full range
VIN = 3.3 V, VOUT = 3.0 V, CL = VIN
Full range
VIN = 1.8 V, VOUT = 1.5 V, CL floating
Full range
VIN = 3.3 V, VOUT = 3.0 V, CL floating
Full range
28
40
60
Rl = 1 Ω, VIN = 3.3 V, VOUT = 2.3 V
Full range
375
435
685
Return from shutdown
VIN = 5 V, ISINK = 10 mA
VOL
OC output logic low voltage
IOH
OC output high leakage current VIN = 5 V, Switch ON
VIN = 1.8 V, ISINK = 10 mA
Ω
0.85
25°C
1
70
85
120
60
80
115
155
175
235
135
165
230
30
45
60
mA
mA
mA
135
Full range
Hysteresis
(1)
(2)
3
0.1
Shutdown threshold
Thermal shutdown (2)
4
1
Full range
VIN = 1.62 V
ON input leakage current
1.3
UNIT
VIN = 3.6 V,
VOUT short to GND
VIN = 1.8 V
ION
5
VIN = 3.6 V, VOUT open
VIN = 3.3 V
ON-state resistance
MAX
1.5
VON = 0 V
VIN = 5.5 V
rON
TYP
125
°C
10
Full range
Full range
0.1
0.2
0.1
0.3
1
V
mA
Full range TA = –40°C to 85°C
See the Application Information section of this data sheet.
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SWITCHING CHARACTERISTICS
VIN = 1.8 V, RL = 50 Ω, CL = 1 mF, TA = –40°C to 85°C, TYP values at TA = 25°C (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
tPWRON
Power-ON time
RL = 50 Ω, CL = 1 mF
192
ms
tPWROFF
Power-OFF time
RL = 50 Ω, CL = 1 mF
0.55
ms
tON
Turn-ON time
RL = 50 Ω, CL = 1 mF
125
ms
tOFF
Turn-OFF time
RL = 50 Ω, CL = 1 mF
115
ms
tR
VOUT rise time
RL = 50 Ω, CL = 1 mF
35
ms
tF
VOUT fall time
RL = 50 Ω, CL = 1 mF
tBLANK
Over-current blanking time
tRSTART
Auto-restart time
(1)
tTIMEOUT
Over-current detection timeout
tOVRTMP
Over-temperature detection maximum
response time
tMODOC
Moderate over-current detection
maximum response time
tHARDSHOR
T
(1)
(2)
(3)
10
Hard-short detection maximum
response time
VIN = VON = 3.3 V, hard short
120
(2)
ms
7
10
15
ms
50
70
95
ms
6000
ms
7.7
ms
VIN = VON = 1.8 V, Moderate over-current
condition (3)
63.5
VIN = VON = 3.3 V, Moderate over-current
condition (3)
65.5
VIN = VON = 1.8 V, hard short (2)
270
VIN = VON = 3.3 V, hard short (2)
295
ms
ms
See the Automatic Disable in Case of Permanent Over Current section in Application Information.
Hard short check is performed at the output voltage of the switch. Hard short condition is active when VOUT < 2/3 VIN. Please refer to
application information.
If the current going through the switch is above ILIM, then the moderate over-current condition is activated
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PARAMETER MEASUREMENT INFORMATION
VIN
ON
VOUT
(A)
TPS22946
RL
CL
+
–
OFF
CIN =1 µF
GND
GND
GND
TEST CIRCUIT
1.8 V
VON
VON
VON/2
VON/2
tr
0V
tON
tOFF
90%
VOUT
VOH
VOUT
tf
0V
VOUT/2
VOUT/2
10%
90%
10%
VOL
tON/tOFF WAVEFORMS
Figure 5. Test Circuit and tON/tOFF Waveforms
VIN
VIN
VIN/2
VIN/2
0V
0V
tPWRON
tPWROFF
VOL
VOUT
VOUT/2
VOUT/2
VOH
VON
Figure 6. tPWRON/tPWROFF Waveforms
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TYPICAL CHARACTERISTICS
ON RESISTANCE
vs
INPUT VOLTAGE
ON RESISTANCE
vs
TEMPERATURE
0.8
0.8
0.7
0.7
V IN = 1.8 V
TA = 85°C
0.6
ON Resistance (Ohm)
ON Resistance (Ohm)
0.6
TA = 25°C
0.5
0.4
TA = -40°C
0.3
0.5
V IN = 3.3 V
0.4
0.3
V IN = 5.5 V
0.2
0.2
0.1
0.1
0
0
-40.00
1.62
1.8
2.5
3.3
5.5
25.00
85.00
Tem perature (°C)
V IN
Figure 7.
Figure 8.
INPUT CURRENT (QUIESCENT)
vs
TEMPERATURE
INPUT CURRENT (LEAKAGE)
vs
TEMPERATURE
600
2.5
V IN = 5.5 V
500
1.5
V IN = 5.5 V
IIN (Leakage) (nA)
IIN (Quiescent) (µA)
2
V IN = 3.3 V
1
V IN = 1.8 V
400
300
200
V IN = 3.3 V
0.5
100
V IN = 1.8 V
0
-40.00
25.00
85.00
0
-40.00
Tem perature (°C)
Figure 9.
12
25.00
85.00
Tem perature (°C)
Figure 10.
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TYPICAL CHARACTERISTICS (continued)
INPUT CURRENT (OFF)
vs
TEMPERATURE
CURRENT LIMIT
vs
TEMPERATURE
450
200
400
180
V IN = 5.5 V
160
350
140
300
120
ILIM (mA)
IIN (Off) (nA)
CL = High
250
200
100
CL = Low
80
150
60
V IN = 3.3 V
CL = Float
100
40
50
20
V IN = 1.8 V
0
-40.00
25.00
0
-50
85.00
-25
Tem perature (°C)
0
25
50
75
100
75
100
Tem perature (°C)
Figure 11.
Figure 12.
CURRENT LIMIT
vs
INPUT VOLTAGE
tBlank
vs
TEMPERATURE
200
11.4
180
CL = High
11.2
V IN = 5.5 V
160
11
V IN = 3.3 V
140
10.8
t Blank (ms)
ILIM (mA)
120
100
CL = Low
80
10.6
V IN = 1.8 V
10.4
60
10.2
CL = Float
40
10
20
0
0
1
2
3
4
5
6
9.8
-50
-25
0
25
50
Tem perature (°C)
V IN (V)
Figure 13.
Figure 14.
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TYPICAL CHARACTERISTICS (continued)
tReset
vs
TEMPERATURE
tPWRON
vs
TEMPERATURE
250
80
78
200
76
t PWRON (µs)
t Restart (ms)
V IN = 5.5 V
74
V IN = 3.3 V
V IN = 1.8 V
72
150
100
70
50
68
66
-50
0
-25
0
25
50
75
-40
100
25
85
Tem perature (°C)
Tem perature (°C)
Figure 15.
Figure 16.
tPWROFF
vs
TEMPERATURE
ON THRESHOLD
6
1
V IN = 5.5 V
0.9
5
0.8
4
V IN = 3.3 V
V OUT (V)
t PWROFF (µs)
0.7
0.6
3
V IN = 2.5 V
0.5
V IN = 1.8 V
2
0.4
V IN = 1.62 V
1
0.3
0.2
-40
25
85
0
0
Tem perature (°C)
1
1.5
2
V ON (V)
Figure 17.
14
0.5
Figure 18.
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APPLICATION INFORMATION
On/Off Control
The ON pin controls the state of the switch. Activating ON continuously holds the switch in the on state so long
as there is no fault. A junction temperature in excess of 150°C overrides the ON control to turn off the switch. ON
is active HIGH and has a low threshold making it capable of interfacing with low voltage signals. When the
MOSFET is off, the body diode is disabled so no current can flow through it from the input to the output, however
it does not prevent reverse current flowing.
Detection Schemes
Over-Temperature Detection
The thermal shutdown detection circuit is active every 8mS for a period of 0.5mS. The thermal shutdown protects
the part from internally or externally generated excessive temperatures. During an over-temperature condition the
switch is turned-off (Open). The switch automatically turns-on (closes) again if temperature of the die drops
below the threshold temperature while the part is still enabled.
In addition, if an over-current fault condition is detected due to a moderate over-current or a hard-short, the
thermal shutdown is activated immediately and stays on continuously for the duration of blanking (see Figure 3).
VIN
VIN/2
0V
VON is tied directly to VIN
VON
0V
tPWRON
VOUT/2
VOUT
140°C
129°C
Normal Temperature
Temperature (°C)
Inrush current window
Over Temperature
Detection
Load Switch Status
SWITCH
OPEN
Over Temperature
resumes the normal cycle
8mS
tOVRTMP
0.5 ms
ON
OFF
ON
Over temperature detected
during the ON cycle
OFF
SWITCH
CLOSE
0.5 ms tOVRTMP
OFF
ON
SWITCH
OPEN
ON
OFF
SWITCH
CLOSE
NOTE: Case where the temperature causes the over-temperature detection circuit to trip before the other detection schemes.
Figure 26. Over-Temperature Detection
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Hard-Short Detection
The hard short detection circuit is active every 250 ms for a period of 125 ms A comparator monitors the output
voltage, VOUT. A hard short is detected when VOUT is lower than 2/3 VIN. The switch then goes into
current-limiting mode.
VIN
VIN/2
0V
VON is tied directly to VIN
VON
0V
A hard short occurs on
Vout
tPWRON
VOUT/2
VOUT
Current increases
through switch
proportional to VOUT
Over current due to hard
short
Current is
limited
No current.
Switch is off
IOUT
tBLANK
tRSTART
tBLANK
tRSTART
tTIMEOUT
Hard short detected during the ON cycle
0.125mS
Hard Short
Detection
OFF
OFF
ON
ON
OFF
tHARDSHORT
Inrush Current window
8 ms
tOVRTMP
Over Temperature
Detection
ON
OFF
tBLANK
Load Switch Status
SWITCH
OPEN
tRSTART
SWITCH
CLOSE
SWITCH
OPEN
tBLANK
SWITCH
CLOSE
tRSTART
SWITCH
OPEN
Figure 27. Hard-Short Detection
16
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SLVS984A – SEPTEMBER 2009 – REVISED FEBRUARY 2010
Moderate Over-Current Detection
The moderate over-current detection circuit is active every 64 ms for a period of 0.5 ms. A moderate over-current
condition is triggered when the output current of the switch exceeds the current limit value and is not yet into
hard short condition. The switch then goes into current-limiting mode.
VIN
0V
VIN/2
VON is tied directly to VIN
VON
0V
A moderate short
occurs on Vout
tPWRON
VOUT/2
VOUT
Current increases
through switch
proportional to VOUT
Over current
Current is
limited
No current
Switch is off
IOUT
Inrush current window
8mS
Moderate Over Current
Detection
OFF
ON
tMODOC
tBLANK
tRSTART
Inrush current window
8mS
Over Temperature
Detection
tTIMEOUT
tOVRTMP
OFF
ON
ON
tBLANK
tRSTART
0.125 ms
Hard Short
Detection
OFF
ON
OFF
ON
OFF
ON
OFF
ON
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
tHARDSHORT
Load Switch Status
SWITCH
OPEN
SWITCH
CLOSE
SWITCH
OPEN
NOTE: The over current does n’t cause the temperature to go above 140°C here.
Figure 28. Moderate Over-Current Detection
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Current Limiting Mode
When an over-current condition (moderate or a hard short) is detected, the TPS22946 operates in a
constant-current mode to prohibit excessive currents from causing damage. TPS22946 has a current limit of
30 mA, 70 mA or 155 mA.
If the constant current condition still persists after 10ms, the device shuts off the switch and pulls the fault signal
pin (OC) low. The TPS22946 has an auto-restart feature which turns the switch on again after 70 ms if the ON
pin is still active.
Fault Reporting
When a moderate over-current, hard short or over-temperature condition is detected, OC is set active low to
signal a fault condition. OC is an open-drain MOSFET and requires a pullup resistor between VIN and OC. During
shutdown, the pulldown on OC is disabled, reducing current draw from the supply.
Power-On / Power-Off Sequence
The device is enabled internally only once the hard-short detection circuit is enabled.
18
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VIN
VIN/2
VON is tied directly to VIN
0V
VON
tPWRON
0V
LDO Output stable
Allotted time for LDO Inrush Current to
exceed normal current limit threshold
VOUT
Temporarily increase current limit threshold to
allow for LDO Inrush current
Current Limit as set by CL
(30 mA, 70 mA, 155 mA)
ILIMIT_INRUSH
tPWRON
Current Limit
Threshold
8 ms
Changes on CL pin, will not affect current
limit threshold after this time
CL pin
Detection
Timing
tCLSET
Inrush Current window
Moderate Over
Current Detection
tMODOC
8 ms
0.5mS
tMODOC
Inrush Current window
Over Temperature
Detection
8 ms
tOVRTMP
0.5mS
0.5mS
0.125mS
Hard Short
Detection
OFF
ON
OFF ON OFF ON
OFF ON OFF ON OFF ON
ON OFF ON
OFF
tHARDSHORT
Load Switch
Status
SWITCH
OPEN
SWITCH
CLOSE
Figure 29. Power-On/Power-Off Sequence Timing
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Automatic Disable in Case of Permanent Over Current
When the switch enters the current-limiting mode due to a hard short condition or a moderate over-current
condition, TPS22946 goes through the 10-ms blanking state and the 70-ms auto restart state. If the hard-short
condition or the moderate over-current condition persists after 5 s, the part shuts off regardless of the ON signal.
The switch is turned on again after a power reset if the ON pin is HIGH.
Inrush Current Timeout Feature
The inrush current required by the LDO at startup can in some cases exceed the current limit and initiate a
blanking (current limiting) condition. TPS22946 provides allowance for this scenario by temporarily increasing the
current limit to 435 mA for 8 ms after the load switch is enabled. This timeout is initiated by the positive edge
transition on the ON signal.
TPS22946
VIN
VIN
ON
ON
VOUT
COUTCL
CL
CIN
GND
OC
TPS72018
VIN
LDO_EN
VOUT
EN
COUTLDO
GND
Figure 30. Inrush Current Timeout Circuit
20
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VIN
VIN/2
VON is tied directly to VIN
0V
VON
tPWRON
0V
LDO Output stable
Allotted time for LDO Inrush Current to
exceed normal current limit threshold
VOUT
Temporarily increase current limit threshold to
allow for LDO Inrush current
Current Limit as set by CL
(30 mA, 70 mA, 155 mA)
ILIMIT_INRUSH
tPWRON
Current Limit
Threshold
8 ms
Allotted time for CL state to be detected.
Changes on CL pin will not affect current limit
threshold after this time.
CL pin
Detection
Timing
tCLSET
Figure 31. Inrush Current Timeout Timing
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CL Control Pin
The TPS22946 supports three current limits: 30 mA, 70 mA, and 155 mA. The current limit selection is
determined by the status of the digital input CL pin, as shown in Table 3. A high impedance, or floating, condition
allows the CL pin to support a third state. The TPS22946 monitors the state of the CL pin during start-up from a
disabled state, and upon start-up sets the current limit accordingly. When floating the CL pin, keep the total
capacitance on the pin less than 100 pF and the resistive loading greater than 10 MΩ to ensure proper
operation. Any changes to the state of the CL pin after the start-up operation has completed are ignored until the
next start-up cycle.
The CL pin must be driven with logic levels referenced to VIN. The CL pin can be tied high or low on the printed
wiring board (PWB) or driven by a general purpose I/O (GPIO), as long as the VIL and VIH recommended
operating conditions are met.
Table 3. CL Control Pin
CL PIN STATUS
CURRENT LIMIT
Logic low (1)
70 mA
Float
(2)
Logic high (1)
(1)
(2)
30 mA
155 mA
Resistance to VCC or GND < 100 Ω
Load on CL: C < 100 pF, R > 10 MΩ
Figure 32. CL Pin Read Timing When cycling VIN (ON Pin Tied to VIN)
Figure 33. CL Pin Read Timing Cycling ON Pin (VIN High)
22
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SLVS984A – SEPTEMBER 2009 – REVISED FEBRUARY 2010
Over Temperature Protection
An over temperature condition occurs when the temperature of the part is greater than 140°C. The OC flag will
go low to indicate a fault. If the over temperature condition persists for more than 6 seconds, the part times out
and shuts OFF. The part has to be enabled by either toggling the ON pin or the VIN pin. If the temperature
reduces below 130°C within 5 seconds, the part will start normal operation.
If the temperature is not constantly high above 140°C and is toggling between greater than 140°C and less than
130°C, the internal timeout timer keeps resetting. If this event occurs more than 32 times, it will cause the part to
shut OFF. It can be enabled by toggling either the ON pin or the VIN pin.
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PACKAGE OPTION ADDENDUM
www.ti.com
7-Oct-2009
PACKAGING INFORMATION
Orderable Device
Status (1)
Package
Type
Package
Drawing
TPS22946YZPR
ACTIVE
DSBGA
YZP
Pins Package Eco Plan (2)
Qty
6
3000 Green (RoHS &
no Sb/Br)
Lead/Ball Finish
SNAGCU
MSL Peak Temp (3)
Level-1-260C-UNLIM
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in
a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check
http://www.ti.com/productcontent for the latest availability information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements
for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered
at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and
package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS
compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame
retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder
temperature.
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Addendum-Page 1
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