DATASHEET
ISL81401, ISL81401A
40V 4-Switch Synchronous Buck-Boost Controller
FN9310
Rev.1.0
May 28, 2021
The
ISL81401
and
ISL81401A
are 4-switch synchronous
buck-boost controller with peak and average current
sensing and monitoring at both ends. The ISL81401 is a
bidirectional device that can conduct current in both
directions while the ISL81401A is an unidirectional
device.
The ISL81401 and ISL81401A use the proprietary
buck-boost control algorithm with valley current
modulation for Boost mode and peak current modulation
for Buck mode control.
The ISL81401 and ISL81401A have four independent
control loops for input and output voltages and currents.
Inherent peak current sensing at both ends and
cycle-by-cycle current limit of this family of products
ensures high operational reliability by providing instant
current limit in fast transient conditions at either ends and
in both directions. It also has two current monitoring pins
at both input and output to facilitate Constant Current
(CC) limit and other system management functions. CC
operation down to low voltages avoids any runaway
condition at over load or short-circuit conditions. In
addition to multilayer overcurrent protection, it also
provides full protection features such as OVP, UVP, OTP,
and average and peak current limit on both input and
output to ensure high reliability in both unidirectional
and bidirectional operation.
The IC is packaged in a space conscious 32 Ld
5mmx5mm QFN package to improve thermal dissipation
and noise immunity. The unique DE/Burst mode at
light-load dramatically lowers standby power
consumption with consistent output ripple over different
load levels.
VIN
R
s_in
Q1
L
PH1
LG1
Q2
Q3
PH2
LG2
Q4
R
s_out
VOUT
Features
• Single inductor 4-switch buck-boost controller
• On-the-fly bidirectional operation with independent
control of voltage and current on both ends
• Proprietary algorithm for smoothest mode transition
• MOSFET drivers with adaptive shoot-through
protection
• Wide input voltage range: 4.5V to 40V
• Wide output voltage range: 0.8V to 40V
• Supports pre-biased output with SR soft-start
• Programmable frequency: 100kHz to 600kHz
• Supports parallel operation current sharing with
cascade phase interleaving
• External sync with clock out or frequency dithering
• External bias for higher efficiency supports 5V - 36V
input
• Output and input current monitor
• Selectable PWM mode operation between
PWM/DE/Burst modes
• Accurate EN/UVLO and PGOOD indicator
• Low shut down current: 2.7µA
• Complete protection: OCP, SCP, OVP, OTP, and UVP
• Dual-level OCP protection with average current
and pulse-by-pulse peak current limit
• Selectable OCP response with either hiccup or
constant current mode
• Negative pulse-by-pulse peak current limit
Applications
• Battery backup
• Type-C power supply and chargers
• Battery powered industrial applications
• Aftermarket automotive
• Redundant power supplies
• Robot and drones
• Medical equipment
• Security surveillance
UG1
UG2
Figure 1. Buck-Boost Power Train Topology
FN9310 Rev.1.0
May 28, 2021
Page 1 of 46
© 2018 Renesas Electronics
ISL81401, ISL81401A
Figure 2. Typical Application Diagram
100
98
96
Efficiency (%)
94
92
90
88
86
84
VIN = 6V
VIN = 12V
VIN = 36V
0
1
2
3
4
5
I
OUT
(A)
6
7
8
9
VIN = 9V
VIN = 24V
82
Figure 3. Efficiency (V
OUT
= 12V, CCM)
FN9310 Rev.1.0
May 28, 2021
Page 2 of 46
ISL81401, ISL81401A
Contents
1.
1.1
1.2
1.3
2.
2.1
2.2
3.
3.1
3.2
3.3
3.4
4.
5.
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
5.10
5.11
5.12
5.13
6.
6.1
6.2
6.3
6.4
6.5
7.
7.1
7.2
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Typical Application Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Pin Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Pin Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Pin Descriptions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thermal Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Recommended Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12
12
13
13
Typical Performance Curves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Internal 5.3V Linear Regulator (VDD), External Bias Supply (EXTBIAS), and 5V
Linear Regulator (VCC5V). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Enable (EN/UVLO) and Soft-Start Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tracking Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Control Loops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Buck-Boost Conversion Topology and Control Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Light-Load Efficiency Enhancement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Prebiased Power-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Frequency Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Phase Lock Loop (PLL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Frequency Synchronization and Dithering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gate Drivers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power-Good Indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25
25
25
27
27
30
33
34
34
34
35
36
37
Protection Circuits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Input Undervoltage Lockout. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VCC5V Power-On Reset (POR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overcurrent Protection (OCP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overvoltage Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Over-Temperature Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
38
38
38
39
39
Layout Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Layout Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
General EPAD Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
FN9310 Rev.1.0
May 28, 2021
Page 3 of 46
ISL81401, ISL81401A
8.
8.1
8.2
8.3
8.4
9.
10.
Component Selection Guideline. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
MOSFET Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inductor Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output Capacitor Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input Capacitor Selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
42
43
43
44
Revision History. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Package Outline Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
FN9310 Rev.1.0
May 28, 2021
Page 4 of 46
FN9310 Rev.1.0
May 28, 2021
Page 5 of 46
ISL81401, ISL81401A
1.
1.1
Overview
Typical Application Schematics
Figure 4. ISL81401EVAL1Z (V
IN
= 6V to 40V, V
OUT
= 12V, I
OUT
= 8A) Evaluation Board Schematic
1. Overview