TI1 LM5041 Cascaded pwm controller Datasheet

LM5041
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SNVS248D – AUGUST 2003 – REVISED MARCH 2013
LM5041 Cascaded PWM Controller
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FEATURES
PACKAGES
•
•
•
•
1
2
•
•
•
•
•
•
•
•
•
•
Internal Start-up Bias Regulator
Programmable Line Under-Voltage Lockout
(UVLO) with Adjustable Hysteresis
Current Mode Control
Internal Error Amplifier with Reference
Dual Mode Over-Current Protection
Leading Edge Blanking
Programmable Push-Pull Overlap or Dead
Time
Internal 1.5A Push-Pull Gate Drivers
Programmable Soft-start
Programmable Oscillator with Sync Capability
Precision Reference
Thermal Shutdown
APPLICATIONS
•
•
•
•
Telecommunication Power Converters
Industrial Power Converters
Multi-Output Power Converters
+42V Automotive Systems
TSSOP-16
WSON-16 (5x5 mm) Thermally Enhanced
DESCRIPTION
The LM5041 PWM controller contains all of the
features necessary to implement either current-fed or
voltage-fed push-pull or bridge power converters.
These “Cascaded” topologies are well suited for
multiple output and higher power applications. The
LM5041’s four control outputs include: the buck stage
controls (HD and LD) and the push-pull control
outputs (PUSH and PULL). Push-pull outputs are
driven at 50% nominal duty cycle at one half of the
switching frequency of the buck stage and can be
configured for either a specified overlap time (for
current-fed applications) or a specified both-off time
(for voltage-fed applications). Push-pull stage
MOSFETs can be driven directly from the internal
gate drivers while the buck stage requires an external
driver such as the LM5102. The LM5041 includes a
high-voltage start-up regulator that operates over a
wide input range of 15V to 100V. The PWM controller
is designed for high-speed capability including an
oscillator frequency range up to 1 MHz and total
propagation delays of less than 100ns. Additional
features include: line Under-Voltage Lockout (UVLO),
soft-start, an error amplifier, precision voltage
reference, and thermal shutdown.
1
2
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.
All trademarks are the property of their respective owners.
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 © 2003–2013, Texas Instruments Incorporated
LM5041
SNVS248D – AUGUST 2003 – REVISED MARCH 2013
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Typical Application Circuit
VOUT
33 - 76V
VDD
HB
VCC
VIN
HD
HI
HO
HS
LD
LM5041
LI
RT
LM5102
2
VSS
LO
RT1 RT2
PUSH
FEED
BACK
PULL
FB
Figure 1. Simplified Cascaded Push-Pull Power Converter
Connection Diagram
1
2
3
4
5
6
7
8
VIN
UVLO
FB
RT
COMP
15
14
TIME
13
REF
SS
HD
CS
LD
AGND
VCC
PGND
PUSH
16
12
11
10
9
PULL
Figure 2. 16-Lead TSSOP, WSON
Package Number PW, NHQ0016A
2
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PIN DESCRIPTION
PIN
NAME
DESCRIPTION
APPLICATION INFORMATION
1
VIN
Source Input Voltage
Input to start-up regulator. Input range 15V to 100V.
2
FB
Feedback Signal
Inverting input for the internal error amplifier. The noninverting input is connected to a 0.75V reference.
3
COMP
Output of the Internal Error Amplifier
There is an internal 5kΩ resistor pull-up on this pin. The
error amplifier provides an active sink.
4
REF
Precision 5 volt reference output
Maximum output current: 10mA. Locally decouple with a
0.1µF capacitor. Reference stays low until the line UV and
the VCC UV are satisfied.
5
HD
Main Buck PWM control output
Buck switch PWM control output. The maximum duty cycle
clamp for this output corresponds to an off time of typically
240ns per cycle. The LM5101 or LM5102 Buck stage gate
driver can be used to level shift and drive the Buck switch.
6
LD
Sync Switch control output
Sync Switch control output. Inversion of HD output. The
LM5101 or LM5102 lower drive can be used to drive the
synchronous rectifier switch.
7
VCC
Output from the internal high voltage start-up
regulator. Regulated to 9 volts.
If an auxiliary winding raises the voltage on this pin above
the regulation setpoint, the internal start-up regulator will
shutdown, reducing the IC power dissipation.
8
PUSH
Output of the push-pull drivers
Output of the push-pull gate driver. Output capability of
1.5A peak .
9
PULL
Output of the push-pull drivers
Output of the push-pull gate driver. Output capability of
1.5A peak.
10
PGND
Power ground
Connect directly to analog ground.
11
AGND
Analog ground
Connect directly to power ground.
12
CS
Current sense input
Current sense input to the PWM comparator (CM control).
There is a 50ns leading edge blanking on this pin. Using
separate dedicated comparators, if CS exceeds 0.5V the
outputs will go into cycle by cycle current limit. If CS
exceeds 0.6V the outputs will be disabled and a soft-start
commenced.
13
SS
Soft-start control
An external capacitor and an internal 10uA current source,
set the soft-start ramp. The controller will enter a low
power state if the SS pin is below the shutdown threshold
of 0.45V
14
TIME
Push-Pull overlap and dead time control
An external resistor (RSET) sets the overlap time or dead
time for the push-pull outputs. A resistor connected
between TIME and GND produces overlap. A resistor
connected between TIME and REF produces dead time.
15
RT / SYNC
Oscillator timing resistor pin and sync
An external resistor sets the oscillator frequency. This pin
will also accept an external oscillator.
16
UVLO
Line Under-Voltage Shutdown
An external divider from the power converter source sets
the shutdown levels. Threshold of operation equals 2.5V.
Hysteresis is set by a switched internal current source
(20µA).
WSON
DAP
SUB
Die substrate
The exposed die attach pad on the WSON package should
be connected to a PCB thermal pad at ground potential.
For additional information on using Texas Instruments' No
Pull Back WSON package, please refer to LLP Application
Note AN-1187 SNOA401.
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Block Diagram
Figure 3. Simplified Block Diagram
9V SERIES
REGULATOR
VIN
VCC
5V
REFERENCE
VCC
ENABLE
VREF
UVLO
UVLO
+
-
2.5V
LOGI
C
UVLO
HYSTERESIS
(20PA)
45PA
CLK
HD
5V
SLOPE COMP
RAMP
GENERATOR
COMP
5k
0.75V
FB
PWM
100k
+
-
S
Q
LD
+
R
1.4V
50k
Q
LOGIC
SS
PGND
CS
2k
0.5V
+
-
CLK + LEB
0.6V
+
AGND
10PA
SS
SS
TIME
+
0.45V
ENABLE
VCC
SHUTDOWN
COMPARATOR
DRIVE
R
OSC
CLK
RT / SYNC
OSCILLATOR
DIVIDE BY 2
OVERLAP
OR
DEAD TIME
CONTROL
PUSH
VCC
DRIVE
R
PULL
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
4
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Absolute Maximum Ratings (1) (2)
VIN to GND
100V
VCC to GND
16V
All Other Inputs to GND
-0.3 to 7V
Junction Temperature
150°C
Storage Temperature Range
-65°C to +150°C
ESD Rating
2 kV
Lead temperature (3)
Wave
4 seconds
260°C
Infrared
10 seconds
240°C
Vapor Phase
75 seconds
219°C
(1)
Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which
operation of the device is intended to be functional. For verified specifications and test conditions, see the Electrical Characteristics.
If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/Distributors for availability and
specifications.
For detailed information on soldering plastic TSSOP and WSON packages, refer to the Packaging Data Book available from Texas
Instruments.
(2)
(3)
Operating Ratings (1)
VIN
15 to 90V
Junction Temperature
(1)
-40°C to +125°C
Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which
operation of the device is intended to be functional. For verified specifications and test conditions, see the Electrical Characteristics.
Electrical Characteristics
Specifications with standard typeface are for TJ = 25°C, and those with boldface type apply over full Operating Junction
Temperature range. VIN = 48V, VCC = 10V, RT = 26.7kΩ, RSET = 20kΩ) unless otherwise stated. (1)
Symbol
Parameter
Conditions
Min
Typ
Max
Units
8.7
9
9.3
V
Startup Regulator
VCC Reg
I-VIN
VCC Regulation
open circuit
(2)
VCC Current Limit
See
Startup Regulator
Leakage (external Vcc
Supply)
VIN = 100V
15
145
25
500
mA
µA
Shutdown Current (Iin)
UVLO = 0V, VCC = open
350
450
µA
VCC Supply
VCC Under-voltage
Lockout Voltage (positive
going Vcc)
VCC Under-voltage
Hysteresis
Supply Current (ICC)
VCC Reg 400mV
VCC Reg - 275mV
1.7
2.1
2.6
V
3
4
mA
CL = 0
V
Error Amplifier
GBW
Gain Bandwidth
3
DC Gain
(1)
(2)
MHz
80
Input Voltage
VFB = COMP
COMP Sink Capability
VFB = 1.5V, COMP= 1V
dB
0.735
0.75
4
8
0.765
V
mA
All limits are specified. All electrical characteristics having room temperature limits are tested during production with TA = TJ = 25°C. All
hot and cold limits are verified by correlating the electrical characteristics to process and temperature variations and applying statistical
process control.
Device thermal limitations may limit usable range.
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Electrical Characteristics (continued)
Specifications with standard typeface are for TJ = 25°C, and those with boldface type apply over full Operating Junction
Temperature range. VIN = 48V, VCC = 10V, RT = 26.7kΩ, RSET = 20kΩ) unless otherwise stated.(1)
Symbol
Parameter
Conditions
Min
Typ
Max
Units
5
5.15
V
25
50
mV
Reference Supply
VREF
Ref Voltage
IREF = 0 mA
Ref Voltage Regulation
IREF = 0 to 10mA
4.85
Ref Current Limit
15
20
mA
40
ns
Current Limit
ILIM Delay to Output
CS Step from 0 to 0.6V
Time to Onset of OUT
Transition (90%)
CL = 0
Cycle by Cycle Threshold
Voltage
Cycle Skip Threshold
Voltage
Resets SS capacitor; auto
restart
0.45
0.5
0.55
V
0.55
0.6
0.65
V
Leading Edge Blanking
Time
CS Sink Current (clocked) CS = 0.3V
2
50
ns
5
mA
Soft-Start
Soft-start Current Source
7
10
13
µA
Soft-start to COMP Offset
0.35
0.55
0.75
V
Shutdown Threshold
0.25
0.5
0.75
V
180
175
200
220
225
kHz
515
600
685
kHz
3
3.5
V
Oscillator
Frequency1 (RT =
26.7KΩ)
TJ = 25°C
Frequency2 (RT =
7.87KΩ)
Sync threshold
PWM Comparator
Delay to Output
COMP set to 2V
CS stepped 0 to 0.4V, Time
to onset of OUT transition
low
Max Duty Cycle
TS = Oscillator Period
Min Duty Cycle
COMP = 0V
25
ns
(Ts-240ns)/Ts)
COMP to PWM
Comparator Gain
%
0
%
0.32
COMP Open Circuit
Voltage
FB = 0V
4.1
4.8
5.5
V
COMP Short Circuit
Current
FB = 0V, COMP = 0V
0.6
1
1.4
mA
Slope Compensation
Slope Comp Amplitude
Delta increase at PWM
Comparator to CS
110
mV
UVLO Shutdown
Under-voltage Shutdown
2.44
2.5
2.56
V
Under-voltage Shutdown
Hysteresis Current
Source
16
20
24
µA
Buck Stage Outputs
Output High level
Output High Saturation
6
5 (VREF)
IOUT = 10mA
REF = VOUT
0.5
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V
1
V
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Electrical Characteristics (continued)
Specifications with standard typeface are for TJ = 25°C, and those with boldface type apply over full Operating Junction
Temperature range. VIN = 48V, VCC = 10V, RT = 26.7kΩ, RSET = 20kΩ) unless otherwise stated.(1)
Symbol
Typ
Max
Units
Output Low Saturation
Parameter
IOUT = −10mA
Conditions
Min
0.5
1
V
Rise Time
CL = 100pF
10
ns
Fall Time
CL = 100pF
10
ns
Push-Pull Outputs
Overlap Time
RSET = 20kΩ Connected to
GND, 50% to 50%
Transitions
60
90
120
ns
Dead Time
RSET = 20kΩ Connected to
REF, 50% to 50%
Transitions
65
95
125
ns
Output High Saturation
IOUT = 50mA
VCC - VOUT
0.25
0.5
V
Output Low Saturation
IOUT = 100mA
0.5
1
Rise Time
CL = 1nF
20
ns
Fall Time
CL = 1nF
20
ns
Thermal Shutdown Temp.
165
°C
Thermal Shutdown
Hysteresis
25
°C
PW Package
125
°C/W
NHQ0016A Package
32
°C/W
V
Thermal Shutdown
TSD
Thermal Resistance
θJA
Junction to Ambient
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Typical Performance Characteristics
VCC and VIN
vs
VIN
VCC
vs
ICC
10
20
VIN
8
VIN = 15V
6
VCC (V)
VCC AND VIN (V)
15
VCC
10
4
5
2
0
0
5
0
15
10
20
0
5
10
15
VIN (V)
ICC (mA)
Figure 4.
Figure 5.
SS Pin Current
vs
Temp
Frequency
vs
RT
13
20
25
1000
FREQUENCY (kHz)
SS CURRENT (PA)
12
11
10
9
8
100
7
-25
25
75
125
10000
1000
Figure 6.
Figure 7.
Overlap Time
vs
RSET
Dead Time
vs
RSET
500
500
400
400
DEAD TIME (ns)
OVERLAP TIME (ns)
TEMPERATURE ( C)
300
200
100
300
200
100
0
0
10
8
100000
RT (:)
o
30
50
70
90
110
10
30
50
70
RSET (k:)
RSET (k:)
Figure 8.
Figure 9.
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90
110
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Typical Performance Characteristics (continued)
Dead Time
vs
Temp
120
130
110
120
DEAD TIME (ns)
OVERLAP TIME (ns)
Overlap Time
vs
Temp
100
RSET = 20k:
90
80
70
110
RSET = 20k:
100
90
80
70
60
-25
25
75
-25
125
25
75
TEMPERATURE (oC)
TEMPERATURE (oC)
Figure 10.
Figure 11.
125
Error Amplifier Gain Phase
Figure 12.
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DETAILED OPERATING DESCRIPTION
The LM5041 PWM controller contains all of the features necessary to implement either current-fed or voltage-fed
push-pull or bridge power converters. These “Cascaded” topologies are well suited for multiple output and higher
power applications. The LM5041’s four control outputs include: the buck stage controls (HD and LD) and the
push-pull control outputs (PUSH and PULL). Push-pull outputs are driven at 50% nominal duty cycle at one half
of the switching frequency of the buck stage and can be configured for either a specified overlap time (for
current-fed applications) or a specified both-off time (for voltage-fed applications). Push-pull stage MOSFETs can
be driven directly from the internal gate drivers while the buck stage requires an external driver such as the
LM5102. The LM5041 includes a high-voltage start-up regulator that operates over a wide input range of 15V to
100V. The PWM controller is designed for high-speed capability including an oscillator frequency range up to 1
MHz and total propagation delays of less than 100ns. Additional features include: line Under-Voltage Lockout
(UVLO), soft-start, an error amplifier, precision voltage reference, and thermal shutdown.
High Voltage Start-Up Regulator
The LM5041 contains an internal high-voltage start-up regulator, thus the input pin (Vin) can be connected
directly to the line voltage. The regulator output is internally current limited to 15mA. When power is applied, the
regulator is enabled and sources current into an external capacitor connected to the Vcc pin. The recommended
capacitance range for the Vcc regulator is 0.1uF to 100uF. When the voltage on the Vcc pin reaches the
regulation point of 9V and the internal voltage reference (REF) reaches its regulation point of 5V, the controller
outputs are enabled. The Buck stage outputs will remain enabled until Vcc falls below 7V or the line UnderVoltage Lockout detector indicates that Vin is out of range. The push-pull outputs continue switching until the
REF pin voltage falls below approximately 3V. In typical applications, an auxiliary transformer winding is
connected through a diode to the Vcc pin. This winding must raise the Vcc voltage above 9.3V to shut off the
internal start-up regulator. Powering VCC from an auxiliary winding improves efficiency while reducing the
controller's power dissipation. The recommended capacitance range for the Vref regulator output is 0.1uF to
10uF.
The external VCC capacitor must be sized such that the capacitor maintains a VCC voltage greater than 7V during
the initial start-up. During a fault mode when the converter auxiliary winding is inactive, external current draw on
the VCC line should be limited so the power dissipated in the start-up regulator does not exceed the maximum
power dissipation of the controller.
An external start-up or other bias rail can be used instead of the internal start-up regulator by connecting the VCC
and the VIN pins together and feeding the external bias voltage into the two pins.
Line Under-Voltage Detector
The LM5041 contains a line Under-Voltage Lockout (UVLO) circuit. An external set-point resistor divider from VIN
to ground sets the operational range of the converter. The divider must be designed such that the voltage at the
UVLO pin will be greater than 2.5V when VIN is in the desired operating range. If the Under-Voltage threshold is
not met, all functions of the controller are disabled and the controller will enter a low-power state with input
current <300µA. ULVO hysteresis is accomplished with an internal 20µA current source that is switched on or off
into the impedance of the set-point divider. When the UVLO threshold is exceeded, the current source is
activated to instantly raise the voltage at the UVLO pin. When the UVLO pin falls below the 2.5V threshold, the
current source is turned off causing the voltage at the UVLO pin to fall. The UVLO pin can also be used to
implement a remote enable / disable function. By shorting the UVLO pin to ground, the converter can be
disabled. The controller can also be disabled through the soft-start pin (SS). The controller will enter a low-power
off state if the SS pin is forced below the 0.45V shutdown threshold.
Buck Stage Control Outputs
The LM5041 Buck switch maximum duty cycle clamp ensures that there will be sufficient off time each cycle to
recharge the bootstrap capacitor used in the high side gate driver. The Buck switch is specified to be off, and the
sync switch on, for at least 250ns per switching cycle. The Buck stage control outputs (LD and HD) are CMOS
buffers with logic levels of 0 to 5V.
During any fault state or Under-Voltage off state, the buck stage control outputs will default to HD low and LD
high.
10
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Push-Pull Outputs
The push pull outputs operate continuously at a nominal 50% duty cycle. A distinguishing feature of the LM5041
is the ability to accurately configure either dead time (both-off) or overlap time (both-on) on the complementary
push-pull outputs. The overlap/dead time magnitude is controlled by a resistor connected to the TIME pin on the
controller. The TIME pin holds one end of the resistor at 2.5V and the other end of the resistor should be
connected to either REF for dead time control setting or to GND for overlap control. The polarity of the current in
the TIME is detected by the LM5041 The magnitude of the overlap/dead time can be calculated as follows:
• Overlap Time (ns) = (3.66 x RSET) + 7
• Overlap Time in ns, RSET connected to GND, RSET in kΩ
• Dead Time (ns) = (3.69 x RSET) + 21
• Dead Time in ns, RSET connected to REF, RSET in kΩ
• Recommended RSET programming range: 10kΩ to 100kΩ
Current-fed designs require a period of overlap to insure there is a continuous path for the buck inductor current.
Voltage-fed designs require a period of dead time to insure there is no time when the push-pull transformer acts
as a shorted turn to the low impedance sourcing node. The push-pull outputs alternate continuously under all
conditions provided REF the voltage is greater than 3V.
K1 * RSET
PUSH
DEADTIME
WAVEFORMS
K1 * RSET
PULL
K2 * RSET
PUSH
OVERLAP
WAVEFORMS
K2 * RSET
PULL
PWM Comparator
The PWM comparator compares the slope compensated current ramp signal to the loop error voltage from the
internal error amplifier (COMP pin). This comparator is optimized for speed in order to achieve minimum
controllable duty cycles. The comparator polarity is such that 0V on the COMP pin will produce zero duty cycle in
the buck stage.
Error Amplifier
An internal high gain wide-bandwidth error amplifier is provided within the LM5041. The amplifier’s non-inverting
input is tied to a 0.75V reference. The inverting input is connected to the FB pin. In non-isolated applications the
power converter output is connected to the FB pin via the voltage setting resistors. Loop compensation
components are connected between the COMP and FB pins. For most isolated applications the error amplifier
function is implemented on the secondary side of the converter and the internal error amp is not used. The
internal error amplifier is configured as an open drain output and can be disabled by connecting the FB pin to
ground. An internal 5kΩ pull-up resistor between the 5V reference and COMP can be used as the pull-up for an
opto-coupler in isolated applications.
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Current Limit/Current Sense
The LM5041 contains two levels of over-current protection. If the voltage at the CS pin exceeds 0.5V the present
buck stage duty cycle is terminated (cycle by cycle current limit). If the voltage at the CS pin overshoots the 0.5V
threshold and exceeds 0.6V, then the controller will terminate the present cycle and fully discharge the soft-start
capacitor. A small RC filter located near the controller is recommended to filter current sense signals at the CS
pin. An internal MOSFET discharges the external CS pin for an additional 50ns at the beginning of each cycle to
reduce the leading edge spike that occurs when the buck stage MOSFET is turned on.
The LM5041 current sense and PWM comparators are very fast, and may respond to short duration noise
pulses. Layout considerations are critical for the current sense filter and sense resistor. The capacitor associated
with the CS filter must be placed close to the device and connected directly to the pins of the controller (CS and
GND). If a current sense transformer is used, both leads of the transformer secondary should be routed to the
sense resistor, which should also be located close to the IC. A resistor may be used for current sensing instead
of a transformer, located in the push-pull transistor sources, but a low inductance type of resistor is required.
When designing with a sense resistor, all of the noise sensitive low power grounds should be connected together
around the IC and a single connection should be made to the high current power ground (sense resistor ground
point).
The second level current sense threshold is intended to protect the power converter by initiating a low duty cycle
hick-up mode when abnormally high currents are sensed. If the second level threshold is reached, the soft-start
capacitor will be discharged and a start-up sequence will commence when the soft-start capacitor is determined
to be fully discharged. The second level threshold will only be reached when a high dV/dt is present at the
current sense pin. The current sense transient must be fast enough to reach the second level threshold before
the first threshold detector turns off the buck stage driver. Very high current sense dV/dt can occur with a
saturated power inductor or shorted load. Excessive filtering on the CS pin such as an extremely low value
current sense resistor or an inductor that does not saturate with excessive loading, may prevent the second level
threshold from being reached. If the second level threshold is never exceeded during an overload condition, the
first level current sense will continue cycle by cycle limiting and the output characteristic of the converter will be
that of a current source. However, a sustained overload current level can cause excessive temperatures in the
power train especially the output rectifiers.
Oscillator and Sync Capability
The LM5041 oscillator is set by a single external resistor connected between the RT pin and GND. To set a
desired oscillator frequency (F), the necessary RT resistor can be calculated from:
RT =
(1/F) - 235 x 10-9
:
182 x 10-12
(1)
The buck stage will switch at the oscillator frequency and each push-pull output will switch at half the oscillator
frequency in a push-pull configuration. The LM5041 can also be synchronized to an external clock. The external
clock must have a higher frequency than the free running frequency set by the RT resistor. The clock signal
should be capacitively coupled into the RT pin with a 100pF capacitor. A peak voltage level greater than 3V is
required for detection of the sync pulse. The sync pulse width should be set in the 15 to 150ns range by the
external components. The RT resistor is always required, whether the oscillator is free running or externally
synchronized. The voltage at the RT pin is internally regulated to 2V. The RT resistor should be located very
close to the device and connected directly to the pins of the IC (RT and GND).
Slope Compensation
The PWM comparator compares the current sense signal to the voltage at the COMP pin. The output stage of
the internal error amplifier generally drives the COMP pin. At duty cycles greater than 50 percent, current mode
control circuits are subject to sub-harmonic oscillation. By adding an additional fixed ramp signal (slope
compensation) to the current sense ramp, oscillations can be avoided. The LM5041 integrates this slope
compensation by buffering the internal oscillator ramp and summing a current ramp generated by the oscillator
internally with the current sense signal. Additional slope compensation may be provided by increasing the source
impedance of the current sense signal.
12
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Product Folder Links: LM5041
LM5041
www.ti.com
SNVS248D – AUGUST 2003 – REVISED MARCH 2013
Soft-start and Shutdown
The soft-start feature allows the power converter to gradually reach the initial steady state operating point,
thereby reducing start-up stresses and surges. At power on, a 10uA current is sourced out of the soft-start pin
(SS) to charge an external capacitor. The capacitor voltage will ramp up slowly and will limit the maximum duty
cycle of the buck stage. In the event of a fault as indicated by VCC Under-voltage, line Under-voltage or second
level current limit, the output drivers are disabled and the soft-start capacitor is discharged to ground. When the
fault condition is no longer present, a soft-start sequence will begin again and buck stage duty cycle will
gradually increase as the soft-start capacitor is charged. The SS pin also serves as an enable input. The
controller will enter a low power state if the SS pin is forced below the 0.45V threshold.
Thermal Protection
Internal Thermal Shutdown circuitry is provided to protect the integrated circuit in the event that the maximum
junction temperature is exceeded. When activated, typically at 165 degrees Celsius, the controller is forced into a
low-power standby state, disabling the output drivers and the bias regulator. This feature is provided to prevent
catastrophic failures from accidental device overheating.
Typical Application
VOUT
T1
L1
33 - 76V
VDD
HB
VDD
HB
VCC
VIN
HD
HI
HO
HO
+
HI
T1
HS
HS
LD
LI
+
LI
LO
LM5100
LM5102
LM5041
VSS
LO
RT2
RT1
PUSH
PULL
COMP
FEED
BACK
Figure 13. Simplified Cascaded Half-Bridge
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Product Folder Links: LM5041
13
LM5041
SNVS248D – AUGUST 2003 – REVISED MARCH 2013
www.ti.com
Application Circuit: Input 35-80V, Output 2.5V, 50A
14
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Product Folder Links: LM5041
LM5041
www.ti.com
SNVS248D – AUGUST 2003 – REVISED MARCH 2013
REVISION HISTORY
Changes from Revision C (March 2013) to Revision D
•
Page
Changed layout of National Data Sheet to TI format .......................................................................................................... 13
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Product Folder Links: LM5041
15
PACKAGE OPTION ADDENDUM
www.ti.com
16-Oct-2015
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
Lead/Ball Finish
MSL Peak Temp
(2)
(6)
(3)
Op Temp (°C)
Device Marking
(4/5)
LM5041MTC/NOPB
ACTIVE
TSSOP
PW
16
92
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
-40 to 125
LM5041
MTC
LM5041MTCX
LIFEBUY
TSSOP
PW
16
2500
TBD
Call TI
Call TI
-40 to 125
LM5041
MTC
LM5041MTCX/NOPB
ACTIVE
TSSOP
PW
16
2500
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
-40 to 125
LM5041
MTC
LM5041SD
NRND
WSON
NHQ
16
1000
TBD
Call TI
Call TI
-40 to 125
5041SD
LM5041SD/NOPB
ACTIVE
WSON
NHQ
16
1000
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
-40 to 125
5041SD
LM5041SDX/NOPB
ACTIVE
WSON
NHQ
16
4500
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
-40 to 125
5041SD
(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.
(4)
There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5)
Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation
of the previous line and the two combined represent the entire Device Marking for that device.
Addendum-Page 1
Samples
PACKAGE OPTION ADDENDUM
www.ti.com
16-Oct-2015
(6)
Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish
value exceeds the maximum column width.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 2
PACKAGE MATERIALS INFORMATION
www.ti.com
6-Nov-2015
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
LM5041MTCX
TSSOP
LM5041MTCX/NOPB
LM5041SD
SPQ
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
B0
(mm)
K0
(mm)
P1
(mm)
W
Pin1
(mm) Quadrant
PW
16
2500
330.0
12.4
6.95
5.6
1.6
8.0
12.0
Q1
TSSOP
PW
16
2500
330.0
12.4
6.95
5.6
1.6
8.0
12.0
Q1
WSON
NHQ
16
1000
178.0
12.4
5.3
5.3
1.3
8.0
12.0
Q1
LM5041SD/NOPB
WSON
NHQ
16
1000
178.0
12.4
5.3
5.3
1.3
8.0
12.0
Q1
LM5041SDX/NOPB
WSON
NHQ
16
4500
330.0
12.4
5.3
5.3
1.3
8.0
12.0
Q1
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
6-Nov-2015
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
LM5041MTCX
TSSOP
PW
16
2500
367.0
367.0
35.0
LM5041MTCX/NOPB
TSSOP
PW
16
2500
367.0
367.0
35.0
LM5041SD
WSON
NHQ
16
1000
210.0
185.0
35.0
LM5041SD/NOPB
WSON
NHQ
16
1000
210.0
185.0
35.0
LM5041SDX/NOPB
WSON
NHQ
16
4500
367.0
367.0
35.0
Pack Materials-Page 2
MECHANICAL DATA
NHQ0016A
SDA16A (Rev A)
www.ti.com
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