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LM5030
100V Push-Pull Current Mode PWM Controller
General Description
The LM5030 High Voltage PWM controller contains all of the
features needed to implement Push-Pull and Bridge topologies, using current-mode control in a small 10 pin package.
This device provides two alternating gate driver outputs. The
LM5030 includes a high-voltage start-up regulator that operates over a wide input range of 14V to 100V. Additional
features include: error amplifier, precision reference, dual
mode current limit, slope compensation, softstart, sync capability and thermal shutdown. This high speed IC has total
propagation delays less than 100ns and a 1MHz capable
single resistor adjustable oscillator.
Package: MSOP-10 (Contact factory for thermally enhanced
LLP availability).
Features
n Internal High Voltage Start-up Regulator
n Single Resistor Oscillator Setting
n Synchronizable
n Error Amplifier
n Precision Reference
n Adjustable Softstart
n Dual Mode Over-Current Protection
n Slope Compensation
n Direct Optocoupler Interface
n 1.5A Peak Gate Drivers
n Thermal Shutdown
Applications
n Telecommunication Power Converters
n Industrial Power Converters
n +42V Automotive Systems
Connection Diagram
Top View
20058112
10-Lead MSOP
Ordering Information
Order Number Package Marking NSC Package Drawing Supplies As
LM5030MM S73B MUB10A 1000 Units on Tape and Reel
LM5030MMX S73B MUB10A 3500 Units on Tape and Reel
August 2003
LM5030 100V Push-Pull Current Mode PWM Controller
© 2003 National Semiconductor Corporation DS200581 www.national.com
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Block Diagram
20058101
FIGURE 1.
LM5030
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Pin Description
Pin Name Pin
Number
Description Application Information
V
IN
1 Source Input Voltage Input to start-up regulator. Input range 14 to 100 Volts.
V
FB
2 Inverting input to the error amplifier The non-inverting input is internally connected to a 1.25 Volt
reference.
COMP 3 Output to the error amplifier There is an internal 5K resistor pull-up on this pin. The error
amplifier provides an active sink.
Vcc 4 Output from the internal high
voltage series pass regulator. The
regulation setpoint is 7.7 Volts.
If an auxiliary winding raises the voltage on this pin above the
regulation setpoint the internal series pass regulator will
shutdown, reducing the IC power dissipation.
OUT1 5 Output of the PWM controller Alternating PWM output gate driver.
OUT2 6 Output of the PWM controller Alternating PWM output gate driver.
GND 7 Return Ground
CS 8 Current sense input Current sense input for current mode control and current limit
sensing. Using separate dedicated comparators, if CS exceeds
0.5 Volt the outputs will go into Cycle by Cycle current limit. If CS
exceeds 0.625V the outputs will be disabled and a softstart
commenced.
RT 9 Oscillator timing resistor pin and
synchronization input.
An external resistor sets the oscillator frequency. This pin will
also accept synchronization pulses from an external oscillator.
SS 10 Dual purpose Softstart and
Shutdown pin
A 10µA current source and an external capacitor set the softstart
timing length. The controller will enter a low power state if the SS
pin is pulled below the typical shutdown threshold of 0.45V.
LM5030
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Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
V
IN
to GND (Survival) -0.3V to 100V
V
CC
to GND (Survival) -0.3V to 16V
RT to GND (Survival) -0.3V to 5.5V
All other pins to GND (Survival) -0.3V to 7V
Power Dissipation (Note 2) Internally Limited
ESD Rating (Note 3)
Human Body Model
Machine Model
2kV
200V
Lead Temperature
(Soldering 4 seconds) 260˚C
Storage Temperature Range -55˚C to +150˚C
Junction Temperature 150˚C
Operating Ratings
Junction Temperature -40˚C to +105˚C
V
IN
14V to 90V
Electrical Characteristics
Specifications in standard type face are for TJ= +25˚C and those in boldface type apply over the full operating junction temperature range. Unless otherwise specified: V
IN
= 48V, VCC= 10V, and RT = 26.7KΩ
Symbol Parameter Conditions Min
(Note 4)
Typ
(Note 5)
Max
(Note 4)
Units
Startup Regulator
V
CC
Reg VCCRegulation open ckt 7.4 7.7 8.0 V
V
CC
Current Limit (Note 2) 10 17 mA
I-V
IN
Startup Regulator Leakage
(external Vcc Supply)
VIN= 90V 150 500 µA
I
IN
Shutdown Current SS = 0V, VCC= open 250 350 µA
V
CC
Supply
V
CC
undervoltage Lockout
Voltage
VccReg
- 300mV
VccReg -
100mV
V
Undervoltage Hysteresis 1.2 1.6 2.1 V
I
CC
Supply Current Cload = 0 2 3 mA
Error Amplifier
GBW Gain Bandwidth 4 MHz
DC Gain 75 dB
Input Voltage V
FB
= COMP 1.220 1.245 1.270 V
COMP Sink Capability V
FB
= 1.5V COMP= 1V 5 13 mA
Current Limit
CS1 Cycle by Cycle CS Threshold
Voltage
0.45 0.5 0.55 V
CS2 Restart CS Threshold Voltage Resets SS capacitor; auto
restart
0.575 0.625 0.675 V
ILIM Delay to Output CS step from 0 to 0.6V
Time to onset of OUT
Transition (90%)
Cload = 0
30 ns
CS Sink Current (clocked) CS = 0.3V 3 6mA
Soft Start/Shutdown
Softstart Current Source 7 10 13 µA
Softstart to COMP Offset 0.25 0.5 0.75 V
Shutdown Threshold 0.2 0.45 0.7 V
LM5030
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Electrical Characteristics (Continued)
Specifications in standard type face are for TJ= +25˚C and those in boldface type apply over the full operating junction temperature range. Unless otherwise specified: V
IN
= 48V, VCC= 10V, and RT = 26.7KΩ
Symbol Parameter Conditions Min
(Note 4)
Typ
(Note 5)
Max
(Note 4)
Units
Oscillator
Frequency1 (RT = 26.7K) 175 200 225 kHz
Frequency2 (RT = 8.2K) 510 600 690 kHz
Sync threshold 3.2 3.8 V
PWM Comparator
Delay to Output COMP set to 2V CS
stepped 0 to 0.4V, Time
to onset of OUT transition
low
30 ns
Max Duty Cycle Inferred from deadtime 47.5 49 50 %
Min Duty Cycle COMP=0V 0 %
COMP to PWM Comparator
Gain
0.34
COMP Open Circuit Voltage V
FB
=0V 4.3 5.2 6.1 V
COMP Short Circuit Current V
FB
= 0V, COMP=0V 0.6 1.1 1.5 mA
Slope Compensation
Slope Comp Amplitude Delta increase at PWM
Comparator to CS
80 105 130 mV
Output Section
Deadtime Cload = 0, 10% to 10% 85 135 185 ns
Output High Saturation Iout = 50mA, V
CC-VOUT
0.25 0.75 V
Output Low Saturation I
OUT
= 100mA 0.25 0.75 V
Rise Time Cload = 1nF 16 ns
Fall Time Cload = 1nF 16 ns
Thermal Shutdown
Tsd Thermal Shutdown Temp. 165 ˚C
Thermal Shutdown Hysteresis 15 ˚C
Note 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 guaranteed specifications and test conditions, see the Electrical Characteristics.
Note 2: The maximum allowable power dissipation is a function of the maximum junction temperature, T
J(MAX)
, the junction-to-ambient thermal resistance, θJA, and
the ambient temperature, T
A
. The maximum allowable power dissipation at any ambient temperture is calculated using:
Where the value of θJAfor the mini SO-10 (MM) package is 200˚C/W. Exceeding the maximum allowable dissipation will cause excessive die temperature, and the
device will go into thermal shutdown.
Note 3: The human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin. The machine model is a 200pF capacitor discharged directly
into each pin. The machine model ESD rating for pin 5 and pin 6 is 150V.
Note 4: Limits are 100% production tested at 25˚C. Limits over the operating temperature range are guaranteed through correlation using Statistical Quality Control
(SQC) methods. The limits are used to calculate National’s Average Outgoing Quality Level (AOQL).
Note 5: Typical numbers represent the most likely parametric norm for 25˚C operation.
LM5030
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Typical Performance Characteristics Unless otherwise specified: T
J
= 25˚C.
V
CC
vs V
IN
VCCvs ICC(VIN= 48V)
20058105 20058107
Oscillator Frequency vs RT
Oscillator Frequency vs Temperature
RT = 26.7kΩ
20058108
20058109
Soft Start Current vs Temperature Deadtime vs Temperature
20058110
20058111
LM5030
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Typical Performance Characteristics Unless otherwise specified: T
J
= 25˚C. (Continued)
Feedback Amplifier Gainphase
20058115
Detailed Operating Description
The LM5030 High Voltage PWM controller contains all of the
features needed to implement Push-Pull and Bridge topologies, using current-mode control in a small 10 pin package.
Features included are, startup regulator, dual mode current
limit, dual alternating gate drivers, thermal shutdown, softstart and slope compensation. This high speed IC has total
propagation delays
<
100nS. The Functional Block Diagram
of the LM5030 is shown in Figure 1.
The LM5030 is designed for Current-Mode Control convert-
ers which require alternating outputs, such as Push-Pull and
Half/Full Bridge topologies. The features included in the
LM5030 enable all of the advantages of Current-Mode Control, line feed-forward, cycle by cycle current limit and simplified loop compensation. The oscillator ramp is internally
buffered and added to the PWM comparator input to provide
slope compensation necessary for current mode control at
higher duty cycles.
High Voltage Start-Up Regulator
The LM5030 contains an internal high voltage startup regulator. The input pin (Vin) can be connected directly to line
voltages as high as 100V. The regulator output is internally
current limited to 10mA. Upon power up, the regulator is
enabled and sources current into an external capacitor connected to the V
CC
pin. The recommended capacitance range
for the V
CC
regulator is 0.1µF to 50µF. When the voltage on
the V
CC
pin reaches the regulation point of 7.7V, the controller outputs are enabled. The outputs will remain enabled
unless, V
CC
falls below 6.1V or if the SS/SHUTDOWN pin is
pulled to ground or an over temperature condition occurs. In
typical applications, an auxiliary transformer winding is diode
connected to the V
CC
pin. This winding raises the V
CC
voltage greater than 8V, effectively shutting off the internal
startup regulator and saving power while reducing the controller dissipation. The external V
CC
capacitor must be sized
such that the self-bias will maintain a V
CC
voltage greater
than 6.1V during the initial start-up. During a fault mode
when the converter self bias winding is inactive, external
current draw on the V
CC
line should be limited as to 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 V
CC
and the Vin
pins and feeding the external bias voltage (8 - 15V) to that
node.
Error Amplifier
An internal high gain error amplifier is provided within the
LM5030. The amplifier’s non-inverting reference is tied to
1.25V. In non-isolated applications the power converter output is connected to the VFB pin via the voltage setting
resistors and loop compensation is connected between the
COMP and VFB pins.
For most isolated applications the error amplifier function is
implemented on the secondary side ground. Since the internal error amplifier is configured as an open drain output it
can be disabled by connecting VFB to ground. The internal
5K pull-up resistor, connected between the 5V reference and
COMP, can be used as the pull-up for an optocoupler or
other isolation device.
PWM Comparator
The PWM comparator compares the 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 discernable duty cycles.
The comparator polarity is such that zero Volts on the COMP
pin will cause a zero duty cycle.
Current Limit/ Current Sense
The LM5030 contains two levels of over-current protection. If
the voltage on the current sense comparator exceeds 0.5
Volts the present cycle is terminated (cycle by cycle current
limit). If the voltage on the current sense comparator exceeds 0.625 Volts, the controller will terminate the present
cycle and discharge the softstart capacitor. A small RC filter,
located near the controller, is recommended for the CS pin.
An internal MOSFET discharges the current sense filter
capacitor at the conclusion of every cycle, to improve dynamic performance.
The LM5030 CS and PWM comparators are very fast, and
as such will 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 very close to the device and connected
directly to the pins of the IC (CS and RTN). Also 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. If a current sense
resistor located in the drive transistor sources is used, for
current sense, a low inductance resistor should be chosen.
LM5030
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Current Limit/ Current Sense
(Continued)
In this case all of the noise sensitive low power grounds
should be commoned together around the IC and then a
single connection should be made to the power ground
(sense resistor ground point).
The second level threshold is intended to protect the power
converter by initiating a low duty cycle hiccup mode when
abnormally high, fast rising currents occur. During excessive
loading, the first level threshold will always be reached and
the output characteristic of the converter will be that of a
current source but this sustained current level can cause
excessive temperatures in the power train especially the
output rectifiers. If the second level threshold is reached, the
softstart capacitor will be fully discharged, a retry will commence following the discharge detection. The second level
threshold will only be reached when a high dV/dt is present
at the current sense pin. The signal must be fast enough to
reach the second level threshold before the first threshold
detector turns off the driver. This can usually happen for a
saturated power inductor or shorted load. Excessive filtering
on the CS pin, extremely low value current sense resistor or
an inductor that does not saturate with excessive loading
may prevent the second level threshold from ever being
reached.
Oscillator, Shutdown and Sync
Capability
The LM5030 oscillator is set by a single external resistor
connected between the RT pin and return. To set a desired
oscillator frequency the necessary RT resistor can be calculated as:
Each output switches at half the oscillator frequency in a
Push-Pull configuration. The LM5030 can also be synchronized to an external clock. The external clock must be of
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 3 Volts with respect to ground 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 a nominal 2 Volts.
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 derived from the COMP pin. The COMP voltage
is set by either the internal error amplifier or an external error
amplifier through an optocoupler. At duty cycles greater than
50% (composite of alternating outputs) current mode control
circuits are prone to subharmonic oscillation. By adding an
additional ramp signal to the current sense ramp signal this
condition can be avoided. The LM5030 integrates this slope
compensation by buffering the internal oscillator ramp and
summing it internally to the current sense (CS) signal. Additional slope compensation may be added by increasing the
source impedance of the current sense signal.
Soft Start/ Shutdown
The softstart feature allows the converter to gradually reach
the initial steady state operating point, thus reducing start-up
stresses and surges. An internal 10uA current source and an
external capacitor generate a ramping voltage signal which
limits the error amplifier output during start-up. In the event
of a second level current limit fault, the softstart capacitor will
be fully discharged which disables the output drivers. When
the fault condition is no longer present, the softstart capacitor is released to ramp and gradually restart the converter.
The SS pin can also be used to disable the controller. If the
SS pin voltage is pulled down below 0.45V (nominal) the
controller will disable the outputs and enter a low power
state.
OUT1, OUT2 and Time Delay
The LM5030 provides two alternating outputs, OUT1 and
OUT2. The internal gate drivers can each sink 1.5A peak
each. The maximum duty cycle for each output is inherently
limited to less than 50%. The typical deadtime between the
falling edge of one gate driver output and the rising edge of
the other gate driver output is 135ns.
Thermal Protection
Internal Thermal Shutdown circuitry is provided to protect the
integrated circuit in the event the excessive junction temperature. When activated, typically at 165 degrees Celsius,
the controller is forced into a low power reset state, disabling
the output drivers and the bias regulator. This feature is
provided to prevent catastrophic failures from accidental
device overheating.
LM5030
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Typical Application Circuit
Typical Application Circuit, 36V - 75VIN and 3.3V, 10A OUT
20058103
LM5030
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ITEM PART NUMBER DESCRIPTION VALUE
C 1 C0805C472K5RAC Capacitor, CER, KEMET 4700p, 50V
C 2 C0805C103K5RAC Capacitor, CER, KEMET 0.01µ, 50V
C 3 C4532X7S0G686M Capacitor, CER, TDK 68µ, 4V
C 4 T520D337M006AS4350 Capacitor, TANT, KEMET 330µ, 6.3V
C 5 T520D337M006AS4350 Capacitor, TANT, KEMET 330µ, 6.3V
C 6 C4532X7R3A103K Capacitor, CER, TDK 0.01µ, 1000V
C 7 C3216X7R2A104K Capacitor, CER, TDK 0.1µ, 100V
C 8 C4532X7R2A105M Capacitor, CER, TDK 1µ, 100V
C 9 C4532X7R2A105M Capacitor, CER, TDK 1µ, 100V
C 10 C0805C102K1RAC Capacitor, CER, KEMET 1000p, 100V
C 11 C1206C223K5RAC Capacitor, CER, KEMET 0.022µ, 50V
C 12 C3216X7R1E105M Capacitor, CER, TDK 1µ, 25V
C 13 C3216COG2J221J Capacitor, CER, TDK 220p, 630V
C 14 C3216COG2J221J Capacitor, CER, TDK 220p, 630V
C 15 C1206C104K5RAC Capacitor, CER, KEMET 0.1µ, 50V
C 16 C0805C101J1GAC Capacitor, CER, KEMET 100p, 100V
C 17 C0805C101J1GAC Capacitor, CER, KEMET 100p, 100V
C 18 C3216X7R1H334K Capacitor, CER, TDK 0.33µ, 50µ
D 1 MBRB3030CTL Diode, Schottky, ON
D 2 CMPD2838-NSA Diode, Signal, Central
D 3 CMPD2838-NSA Diode, Signal, Central
D 4 CMPD2838-NSA Diode, Signal, Central
D 5 CMPD2838-NSA Diode, Signal, Central
L 1 MSS6132-103 Input Choke, Coilcraft 10µH, 1.5A
L 2 A9785-B Output Choke, Coilcraft 7µH
R 1 CRCW12061R00F Resistor 1
R 2 CRCW12064990F Resistor 499
R 3 CRCW2512101J Resistor 100, 1W
R 4 CRCW2512101J Resistor 100, 1W
R 5 CRCW12064022F Resistor 40.2K
R 6 CRCW120610R0F Resistor 10
R 7 CRCW120610R0F Resistor 10
R 8 CRCW12061002F Resistor 10K
R 9 CRCW120623R7F Resistor 23.7
R 10 CRCW12062002F Resistor 20K
R 11 CRCW120610R0F Resistor 10
R 12 CRCW12063010F Resistor 301
R 13 CRCW120610R0F Resistor 10
R 14 CRCW12061001F Resistor 1K
TX 1 A9784-B POWER XFR, COILCRAFT
TX 2 P8208T CURRENT XFR, Pulse 100:1
U1 1 LM5030 REGULATOR, NATIONAL
U2 2 MOCD207M OPTO-COUPLER, QT
OPTOELECTRONICS
U3 3 LM3411AM5-3.3 REFERENCE, NATIONAL
651-1727010 DUAL TERMINALS, MOUSER 3 per ASSY
X 1 SUD19N20-90 FET, N, 200V, SILICONIX
X 2 SUD19N20-90 FET, N, 200V, SILICONIX
LM5030
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Physical Dimensions inches (millimeters)
unless otherwise noted
10 Lead MSOP Package
NS Package Number MUB10A
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DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or
systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and
whose failure to perform when properly used in
accordance with instructions for use provided in the
labeling, can be reasonably expected to result in a
significant injury to the user.
2. A critical component is any component of a life
support device or system whose failure to perform
can be reasonably expected to cause the failure of
the life support device or system, or to affect its
safety or effectiveness.
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LM5030 100V Push-Pull Current Mode PWM Controller
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.
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