Linear Technology DC1555B, Демонстрационное руководство

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dc1555bfa
DEMO MANUAL DC1555B
Description
LTC4365: High Voltage
UV, OV and Reverse Supply
Protection Controller
Demonstration circuit DC1555B is intended to demonstrate
the performance of the LTC4365 High Voltage Undervoltage
(UV), Overvoltage (OV) and Reverse Supply Protection
Controller.
The LTC4365 protects circuits from input voltages that may
be too high, too low or negative. It operates by controlling
the gates of two back-to-back connected MOSFETs to keep
the output in a safe range. The OV and UV protection levels
are adjusted by resistive dividers at the OV and UV pins.
Asserting the SHDN pin disables the MOSFETs and places
the LTC4365 in a low-current shutdown state. The FAULT
pin is asserted when the Controller is in shutdown mode
L
, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
perForMAnce sUMMArY
(T
A
= 25°C)
or when the input voltage is outside of the UV or OV level.
The LTC4365 can withstand DC voltages between –40V
and 60V and has a valid operating range of 2.5V to 34V.
The DC1555B includes the LTC4365 Controller, two back-
to-back connected power MOSFETs, three jumpers and
three LEDs to indicate the input and output voltages and
the FAULT pin signal.
Design files for this circuit board are available at
http://www.linear.com/demo
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
Board Input Voltage Range –30 30 V
V
IN(UVLO)
Input Supply Undervoltage Lockout V
IN
Rising 1.8 2.2 2.4 V
I
VIN
Input Supply Current SHDN = 0V
SHDN = 2.5V
10
25
50
150
µA
µA
I
VIN(R)
Reverse Input Supply Current V
IN
= –40V, V
OUT
= 0V –1.2 –1.8 mA
ΔV
GATE
External N-Channel Gate Drive (GATE – V
OUT
) V
IN
= V
OUT
= 5V, I
GATE
= –1µA
V
IN
= V
OUT
= 12V to 34V, I
GATE
= –1µA
3
7.4
3.6
8.4
4.2
9.8
V
V
I
GATE(UP)
External N-Channel Gate Pull-Up current GATE = V
IN
= V
OUT
= 12V –12 –20 –30 µA
I
GATE(FAST)
External N-Channel Fast Gate Pull-Down Current Fast Shutdown, GATE = 20V, V
IN
= V
OUT
= 12V 31 50 72 mA
I
GATE(SLOW)
External N-Channel Gentle Gate Pull-Down Current Gentle Shutdown, GATE = 20V, V
IN
= V
OUT
= 12V 50 90 150 µA
V
UV
UV Input Threshold Voltage UV Falling → ΔV
GATE
= 0V 492.5 500 507.5 mV
V
OV
OV Input Threshold Voltage OV Rising → ΔV
GATE
= 0V 492.5 500 507.5 mV
t
GATE(FAST)
External N-Channel Fast Gate Turn-Off Delay C
GATE
= 2.2nF, UV or OV Fault 2 4 µs
t
FAULT
OV, UV Fault Propagation Delay Overdrive = 50mV, V
IN
= V
OUT
= 12V 1 2 µs
V
SHDN
SHDN Input Threshold SHDN Falling to ΔV
GATE
= 0V 0.4 0.75 1.2 V
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