Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsPMICsPMIC - voltage regulators - DC DC switch controllers TSSOP 16

Main

Output

3.3V

BIAS

AGND

COMP

Sync

PGND

OUT

RAMP

LM5115

Auxiliary

Output

2.0V

+12V

FEEDBACK

Main Converter

PWM Controller

INPUT

Phase Signal

LM5115

www.ti.com

SNVS343E –MARCH 2005–REVISED MARCH 2013

LM5115 Secondary Side Post Regulator / Synchronous Buck Controller

Check for Samples: LM5115

FEATURES

DESCRIPTION

The LM5115 is a versatile switching regulator

• Self-Synchronization to Main Channel Output

controller. It has two main application configurations.

• Standalone DC/DC Synchronous Buck Mode

The first is utilizing the Secondary Side Post

• Leading Edge Pulse Width Modulation

Regulation (SSPR) technique to implement multiple

output power converters. In the second configuration,

• Voltage-Mode Control with Current Injection

it can be used as a standalone synchronous buck

and Input Line Feed-Forward

controller (Please see Standalone DC/DC

• Operates from AC or DC Input up to 75V

Synchronous Buck Mode for more details). The

• Wide 4.5V to 30V Bias Supply Range

SSPR technique develops a highly efficient and well

regulated auxiliary output from the secondary side

• Wide 0.75V to 13.5V Output Range.

switching waveform of an isolated power converter.

• Top and Bottom Gate Drivers Sink 2.5A Peak

Regulation of the auxiliary output voltage is achieved

• Adaptive Gate Driver Dead-Time Control

by leading edge pulse width modulation (PWM) of the

main channel duty cycle. Leading edge modulation is

• Wide Bandwidth Error Amplifier (4MHz)

compatible with either current mode or voltage mode

• Programmable Soft-Start

control of the main output. The LM5115 drives

• Thermal Shutdown Protection

external high side and low side NMOS power

switches configured as a synchronous buck regulator.

• TSSOP-16 or Thermally Enhanced WSON-16

A current sense amplifier provides overload

Packages

protection and operates over a wide common mode

input range. Additional features include a low dropout

(LDO) bias regulator, error amplifier, precision

reference, adaptive dead time control of the gate

signals and thermal shutdown.

Typical Application Circuit

Figure 1. Simplified Multiple Output Power Converter Utilizing SSPR Technique

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.

2All 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.

Summary of content (24 pages)

PAGE 1
LM5115 www.ti.com SNVS343E – MARCH 2005 – REVISED MARCH 2013 LM5115 Secondary Side Post Regulator / Synchronous Buck Controller Check for Samples: LM5115 FEATURES DESCRIPTION • • • • The LM5115 is a versatile switching regulator controller. It has two main application configurations. The first is utilizing the Secondary Side Post Regulation (SSPR) technique to implement multiple output power converters.
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LM5115 SNVS343E – MARCH 2005 – REVISED MARCH 2013 www.ti.com Connection Diagram 16 VBIAS CS 1 1 2 3 4 5 6 7 8 CS VOUT AGND CO COMP FB VBIAS HB HO HS VCC LO SS PGND RAMP SYNC 16 15 VOUT 2 15 HB AGND 3 14 HO CO 4 COMP 5 14 13 EP 13 HS 12 VCC FB 6 11 LO SS 7 10 PGND RAMP 8 9 SYNC 12 11 Figure 3. 16-Lead WSON Package Numbers NHQ0016A 10 9 Figure 2.
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LM5115 www.ti.com SNVS343E – MARCH 2005 – REVISED MARCH 2013 Pin Descriptions (continued) Pin Name 16 VBIAS - Description Application Information Supply Bias Input Input to the LDO bias regulator and current sense amplifier that powers internal blocks. Input range of VBIAS is 4.5V to 30V. Exposed Pad Exposed Pad, underside of WSON package (WSON Package Only) Internally bonded to the die substrate. Connect to system ground for low thermal impedance.
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LM5115 SNVS343E – MARCH 2005 – REVISED MARCH 2013 Absolute Maximum Ratings www.ti.com (1) (2) VBIAS to GND –0.3V to 32V VCC to GND –0.3V to 9V HS to GND –1V to 76V VOUT, CS to GND – 0.3V to 15V −0.3V to 7.0V All other inputs to GND Storage Temperature Range –55°C to +150°C Junction Temperature +150°C ESD Rating HBM (3) (1) (2) (3) 2 kV Absolute Maximum Ratings indicate limits beyond which damage to the component may occur.
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LM5115 www.ti.com SNVS343E – MARCH 2005 – REVISED MARCH 2013 Electrical Characteristics (continued) Unless otherwise specified, TJ = –40°C to +125°C, VBIAS = 12V, No Load on LO or HO. SYMBOL PARAMETER FB Input Bias Current GBW Vio CONDITIONS MIN FB = 2V TYP MAX UNITS 0.2 0.
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LM5115 SNVS343E – MARCH 2005 – REVISED MARCH 2013 www.ti.com Electrical Characteristics (continued) Unless otherwise specified, TJ = –40°C to +125°C, VBIAS = 12V, No Load on LO or HO. SYMBOL PARAMETER SYNC Rise to LO Fall Delay CONDITIONS MIN CLOAD = 0 TYP MAX UNITS 50 ns 165 °C 25 °C THERMAL SHUTDOWN TSD Thermal Shutdown Temp.
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LM5115 www.ti.com SNVS343E – MARCH 2005 – REVISED MARCH 2013 Typical Performance Characteristics Efficiency vs. Load Current and Vphase VCC Regulator Start-up Characteristics, VCC vs. VBIAS 100 16 Vphase = 6V 98 96 12 94 Vphase = 8V 10 92 90 VCC (V) EFFICIENCY (%) VBIAS 14 Vphase = 12V 88 6 86 4 84 2 82 0 1 2 3 4 5 6 VCC 8 0 7 0 2 4 6 8 10 12 14 16 LOAD (A) VBIAS (V) Figure 4. Figure 5. Current Value (CV) vs.
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LM5115 SNVS343E – MARCH 2005 – REVISED MARCH 2013 www.ti.com Typical Performance Characteristics (continued) Common Mode Output Voltage vs. Positive Current Limit 14 Common Mode Output Voltage vs. Negative Current Limit (Room Temp) 12 27oC 12 10 -40oC 8 125oC 8 VOUT (V) VOUT (V) 10 6 6 4 4 2 2 0 0 10 20 30 40 0 -20 50 VCL (mV) -19 -18 -17 -16 -15 VCL (mV) Figure 10. Figure 11.
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LM5115 www.ti.com SNVS343E – MARCH 2005 – REVISED MARCH 2013 DETAILED OPERATING DESCRIPTION The LM5115 controller contains all of the features necessary to implement multiple output power converters utilizing the Secondary Side Post Regulation (SSPR) technique. The SSPR technique develops a highly efficient and well regulated auxiliary output from the secondary side switching waveform of an isolated power converter.
PAGE 10
LM5115 SNVS343E – MARCH 2005 – REVISED MARCH 2013 www.ti.com The RAMP and SYNC functions illustrated in Figure 13 provide line voltage feed-forward to improve the regulation of the auxiliary output when the input voltage of the main converter changes. Varying the input voltage to the main converter produces proportional variations in amplitude of the phase signal.
PAGE 11
LM5115 www.ti.com SNVS343E – MARCH 2005 – REVISED MARCH 2013 Error Amplifier and Soft-Start (FB, CO, & COMP, SS) An internal wide bandwidth error amplifier is provided within the LM5115 for voltage feedback to the PWM controller. The amplifier’s inverting input is connected to the FB pin. The output of the auxiliary converter is regulated by connecting a voltage setting resistor divider between the output and the FB pin.
PAGE 12
LM5115 SNVS343E – MARCH 2005 – REVISED MARCH 2013 www.ti.com Leading edge modulation of the auxiliary PWM controller is required if the main converter is implemented with peak current mode control. If trailing edge modulation were used, the additional load on the transformer secondary from the auxiliary channel would be drawn only during the first portion of the phase signal pulse.
PAGE 13
LM5115 www.ti.com SNVS343E – MARCH 2005 – REVISED MARCH 2013 Injecting a signal proportional to the instantaneous inductor current into a voltage mode controller improves the control loop stability and bandwidth. This current injection eliminates the lead R-C lead network in the feedback path that is normally required with voltage mode control (see Figure 18).
PAGE 14
LM5115 SNVS343E – MARCH 2005 – REVISED MARCH 2013 www.ti.com A current limit fold-back feature is provided by the LM5115 to reduce the peak output current delivered to a shorted load. When the common mode input voltage to the current sense amplifier (CS and VOUT pins) falls below 2V, the current limit threshold is reduced from the normal level. At common mode voltages > 2V, the current limit threshold is nominally 45mV.
PAGE 15
LM5115 www.ti.com SNVS343E – MARCH 2005 – REVISED MARCH 2013 See the LM5115 dc evaluation board application note (AN-1367 SNVA106) for more details on the synchronous buck mode. Input 7-70 VDC +12V Vcc Sync HB LM5115 Vbias HO RAMP HS SS LO Rs Output 5V@6A CO CS VOUT FB PGND AGND COMP Figure 19. Simplified Typical Application Circuit (Synchronous Buck Mode) 100 VIN = 7V EFFICIENCY (%) 95 90 85 VIN = 48V VIN = 24V 80 VIN = 70V 75 70 1 2 3 4 5 6 LOAD (A) Figure 20. Efficiency vs.
PAGE 16
LM5115 SNVS343E – MARCH 2005 – REVISED MARCH 2013 www.ti.com Application Circuit Figure 21.
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LM5115 www.ti.com SNVS343E – MARCH 2005 – REVISED MARCH 2013 REVISION HISTORY Changes from Revision D (March 2013) to Revision E • Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 1-Nov-2013 (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.
PAGE 20
PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing LM5115MTCX TSSOP LM5115MTCX/NOPB LM5115SD/NOPB LM5115SDX/NOPB 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 8.3 1.6 8.0 12.0 Q1 TSSOP PW 16 2500 330.0 12.4 6.95 8.3 1.6 8.0 12.0 Q1 WSON NHQ 16 1000 178.0 12.4 5.3 5.3 1.3 8.0 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM5115MTCX TSSOP PW 16 2500 367.0 367.0 35.0 LM5115MTCX/NOPB TSSOP PW 16 2500 367.0 367.0 35.0 LM5115SD/NOPB WSON NHQ 16 1000 210.0 185.0 35.0 LM5115SDX/NOPB WSON NHQ 16 4500 367.0 367.0 35.
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MECHANICAL DATA NHQ0016A SDA16A (Rev A) www.ti.
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