Boost Controller. LM5121 Datasheet

LM5121 Controller. Datasheet pdf. Equivalent

LM5121 Datasheet
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Part LM5121
Description Wide Input Synchronous Boost Controller
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LM5121, LM5121-Q1
SNVS963C – SEPTEMBER 2013 – REVISED JUNE 2016
LM5121/-Q1 Wide Input Synchronous Boost Controller with Disconnection Switch Control
1 Features
1 AEC-Q100 Qualified with the following results:
– Device Temperature Grade 1: -40°C to +125°C
Ambient Operating Temperature Range
– Device HBM ESD Classification Level 2
– Device CDM ESD Classification Level C6
• Maximum Input Voltage: 65 V
• Min Input Voltage: 3.0 V (4.5 V for startup)
• Output Voltage Up to 100 V
• Bypass (VOUT = VIN) Operation
• 1.2-V Reference with ±1.0% Accuracy
• Free-Run/Synchronizable up to 1 MHz
• Peak Current Mode Control
• Robust Integrated 3-A Gate Drivers
• Adaptive Dead-Time Control
• Optional Diode Emulation Mode
• Programmable Cycle-by-Cycle Current Limit
• Programmable Line UVLO
• Programmable Soft-Start
• Thermal Shutdown Protection
• Low Shutdown Quiescent Current: 9 μA
• Programmable Slope Compensation
• Programmable Skip Cycle Mode Reduces
Standby Power
• Supports External VCC Bias Supply Option
• Load Disconnection in Shutdown Mode (True
Shutdown)
• Inrush Current Limiting
• Hiccup Mode Short Circuit/Overload Protection
• Circuit Breaker Function
• Capable of Input Transient Suppression
• Capable of Reverse Battery Protection
• Thermally Enhanced 20-Pin HTSSOP
2 Applications
• 12-V, 24-V, and 48-V Power Systems
• Automotive Start-Stop
• High Current Boost Power Supply
• Battery Powered System
3 Description
The LM5121 is a synchronous boost controller
intended for high-efficiency, high-power boost
regulator applications. The control method is based
upon peak current mode control. Current mode
control provides inherent line feed-forward, cycle-by-
cycle current limiting and ease of loop compensation.
The switching frequency is programmable up to 1
MHz. Higher efficiency is achieved using two robust
N-channel MOSFET gate drivers with adaptive dead-
time control. A user-selectable diode emulation mode
enables discontinuous mode operation for improved
efficiency at light load conditions.
The LM5121 provides disconnection switch control
which completely disconnects the output from the
input during an output short or a shutdown condition.
During start-up sequence, inrush current is limited by
the disconnection switch control.
An internal charge pump allows 100% duty cycle
operation of the high-side synchronous switch
(Bypass operation). Additional features include
thermal shutdown, frequency synchronization, hiccup
mode current limit and adjustable line undervoltage
lockout.
Device Information(1)
PART NUMBER PACKAGE
BODY SIZE (NOM)
LM5121
LM5121-Q1
HTSSOP (20)
6.50 mm x 4.40 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
Simplified Application Diagram
VIN VOUT
VCC BST
DS
DG
CSN
CSP
VIN
UVLO
SLOPE
SYNCIN/RT
LM5121
SW
LO
HO
COMP
FB
RES
SS
MODE
PGND
AGND
+
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.



Texas Instruments LM5121
LM5121, LM5121-Q1
SNVS963C – SEPTEMBER 2013 – REVISED JUNE 2016
www.ti.com
Table of Contents
1 Features .................................................................. 1
2 Applications ........................................................... 1
3 Description ............................................................. 1
4 Revision History..................................................... 2
5 Pin Configuration and Functions ......................... 3
6 Specifications......................................................... 4
6.1 Absolute Maximum Ratings ...................................... 4
6.2 ESD Ratings: LM5121 .............................................. 5
6.3 ESD Ratings: LM5121-Q1 ........................................ 5
6.4 Recommended Operating Conditions....................... 5
6.5 Thermal Information .................................................. 5
6.6 Electrical Characteristics........................................... 6
6.7 Typical Characteristics .............................................. 9
7 Detailed Description ............................................ 12
7.1 Overview ................................................................. 12
7.2 Functional Block Diagram ....................................... 12
7.3 Feature Description................................................. 13
7.4 Device Functional Modes........................................ 21
8 Application and Implementation ........................ 24
8.1 Application Information............................................ 24
8.2 Typical Application .................................................. 32
9 Power Supply Recommendations...................... 40
10 Layout................................................................... 40
10.1 Layout Guidelines ................................................. 40
10.2 Layout Example .................................................... 40
11 Device and Documentation Support ................. 41
11.1 Related Links ........................................................ 41
11.2 Receiving Notification of Documentation Updates 41
11.3 Community Resources.......................................... 41
11.4 Trademarks ........................................................... 41
11.5 Electrostatic Discharge Caution ............................ 41
11.6 Glossary ................................................................ 41
12 Mechanical, Packaging, and Orderable
Information ........................................................... 41
4 Revision History
Changes from Revision B (December 2014) to Revision C
Page
• Added Automotive ESD Features........................................................................................................................................... 1
• Changed equation ............................................................................................................................................................... 20
Changes from Revision A (September 2013) to Revision B
Page
• Added Pin Configuration and Functions section, Handling Rating table, Feature Description section, Device
Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout
section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information
section ................................................................................................................................................................................... 1
2 Submit Documentation Feedback
Copyright © 2013–2016, Texas Instruments Incorporated
Product Folder Links: LM5121 LM5121-Q1



Texas Instruments LM5121
www.ti.com
5 Pin Configuration and Functions
LM5121, LM5121-Q1
SNVS963C – SEPTEMBER 2013 – REVISED JUNE 2016
DS
DG
CSN
CSP
VIN
UVLO
SS
SYNCIN/RT
AGND
FB
HTSSOP
PWP Package
TOP VIEW
1
2
3
4
5
EP
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
BST
HO
SW
VCC
LO
PGND
RES
MODE
SLOPE
COMP
NAME
AGND
PIN
NO.
9
BST 20
COMP
CSN
CSP
DG
DS
EP
FB
HO
LO
11
3
4
2
1
EP
10
19
16
MODE
13
Pin Functions
I/O (1)
DESCRIPTION
G Analog ground connection. Return for the internal voltage reference and analog circuits.
High-side driver supply for bootstrap gate drive. Connect to the cathode of the external bootstrap
P/I
diode and to the bootstrap capacitor. The bootstrap capacitor supplies current to charge the high-
side N-channel MOSFET gate and should be placed as close to controller as possible. An internal
BST charge pump will supply 200 µA current into bootstrap capacitor for bypass operation.
O
Output of the internal error amplifier. The loop compensation network should be connected between
this pin and the FB pin.
I Inverting input of current sense amplifier. Connect to the negative-side of the current sense resistor.
I
Non-inverting input of current sense amplifier. Connect to the positive-side of the current sense
resistor.
O
Disconnection switch control pin. Connect to the gate terminal of the N-channel MOSFET
disconnection switch.
Source connection of N-channel MOSFET disconnection switch. Connect to the source terminal of
I/O the disconnection switch, the cathode terminal of the freewheeling diode and the supply input of
boost inductor.
N/A
Exposed pad of the package. No internal electrical connections. Should be soldered to the large
ground plane to reduce thermal resistance.
I
Feedback. Inverting input of the internal error amplifier. A resistor divider from the output to this pin
sets the output voltage level. The regulation threshold at the FB pin is 1.2 V.
O
High-side N-channel MOSFET gate drive output. Connect to the gate of the high-side synchronous
N-channel MOSFET switch through a short, low inductance path.
O
Low-side N-channel MOSFET gate drive output. Connect to the gate of the low-side N-channel
MOSFET switch through a short, low inductance path.
Switching mode selection pin. Internal 700 kΩ pull-up and 100 kΩ pull-down resistor hold MODE pin
to 0.15 V as a default. By adding external pull-up or pull-down resistor, MODE pin voltage can be
programmed. When MODE pin voltage is greater than 1.2 V, diode emulation mode threshold,
forced PWM mode is enabled, allowing current to flow in either direction through the high-side N-
I channel MOSFET switch. When MODE pin voltage is less than 1.2 V, the controller works in diode
emulation mode. Skip cycle comparator is activated as a default condition when the MODE pin is
left floating. If the MODE pin is grounded, the controller still operates in diode emulation mode, but
the skip cycle comparator will not be triggered in normal operation, this enables pulse skipping
operation at light load.
(1) G = Ground, I = Input, O = Output, P = Power
Copyright © 2013–2016, Texas Instruments Incorporated
Product Folder Links: LM5121 LM5121-Q1
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