LM5116
SNVS499G –FEBRUARY 2007–REVISED MARCH 2013
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BLOCK DIAGRAM AND TYPICAL APPLICATION CIRCUIT
VCCX
17
VCCX
C
VCCX
LM 5116
+
-
4.5V
V
IN
6V-100V
R
VCC
1
4
2
16
VIN
7. 4 V
REGULATOR
UVLO
C
EN
VCC
D1
C
IN
SLEEP
MODE
SHUTDOWN
EN
EN
D2
STANDBY
1.215V
HB 18
THERMAL
SHUTDOWN
R
R
5 mA
UV2
UV1
UVLO
UVLO
LOGIC
C
FT
DIS
C
HB
HICCUP FAULT TIMER
256 CLOCK CYCLES
UVLO
V
IN
DRIVER
HO 19
CLK
Q1
10 mA
S
R
Q
Q
L1
SS
ADAPTIVE
TIMER
7
8
VOUT
3V
1V
SW 20
PWM
C
SS
VCC
DRIVER
1.215V
FB
Q2
C
CURRENT
LIMIT
SNUB
LO 15
C
OUT
R
SNUB
12
CS
TRACK
SAMPLE
and
C
ERROR
AMP
COMP
1.6V
10 x RS V/A
0.5V
A =10
C
HF
R
S
HOLD
R
COMP
13
CSG
COMP
9
+
CLK
DIODE
EMULATION
CONTROL
SW
11
DEMB
SS
VOUT 10
VIN
CLK
C
SYNC
SYNC
RT/SYNC
3
OSCILLATOR
R
FB2
RAMP GENERATOR
= 5mA/V x (VIN - VOUT) + 25 mA
I
R
R
T
IR
R
FB1
RAMP
AGND
PGND
5
6
14
C
RAMP
Figure 26. Typical Application
Detailed Operating Description
The LM5116 high voltage switching regulator features all of the functions necessary to implement an efficient
high voltage buck regulator using a minimum of external components. This easy to use regulator integrates high-
side and low-side MOSFET drivers capable of supplying peak currents of 2 Amps. The regulator control method
is based on current mode control utilizing an emulated current ramp. Emulated peak current mode control
provides inherent line feed-forward, cycle by cycle current limiting and ease of loop compensation. The use of an
emulated control ramp reduces noise sensitivity of the pulse-width modulation circuit, allowing reliable processing
of the very small duty cycles necessary in high input voltage applications. The operating frequency is user
programmable from 50 kHz to 1 MHz. An oscillator/synchronization pin allows the operating frequency to be set
by a single resistor or synchronized to an external clock. Fault protection features include current limiting, thermal
shutdown and remote shutdown capability. An under-voltage lockout input allows regulator shutdown when the
input voltage is below a user selected threshold, and an enable function will put the regulator into an extremely
low current shutdown via the enable input. The HTSSOP-20 package features an exposed pad to aid in thermal
dissipation.
12
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