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Description
Demonstration circuit DC1717A uses the
arbitrate between three input supply rails, selecting the
highest priority, valid supply to power the load. The rail's
priority is defined by the input connection (V1-V3). Each
rail has overvoltage and undervoltage thresholds set by
external resistors. If the highest priority rail voltage falls
out of the defined window (overvoltage or undervoltage),
the rail with the next highest priority, which is valid, is
performance summary
SYMBOL
PARAMETER
V1-V3, V
V1 to V3, V
Operating Supply Range
OUT
OUT
ΔV
Open (VS-VG) Clamp Voltage
G
ΔV
Sourcing (VS-VG) Clamp Voltage
G(SOURCE)
ΔV
Sinking (VS-VG) Clamp Voltage
G(SINK)
ΔV
G1 to G3 Off (VS-VG) Threshold
G(OFF)
ΔV
G1 to G3 Pull-Down Slew Rate
G(SLEW,ON)
ΔV
G1 to G3 Pull-Up Slew Rate
G(SLEW,OFF)
I
G1 to G3 Low Pull-Down Current
GATE(LOW)
V
Reverse Voltage Threshold
REV
t
Break-Before-Make Time
G(SWITCHOVER)
V
VALID1 to VALID3 Output Low Voltage
VALID(OL)
t
VALID1 to VALID3 Delay OFF from
PVALID(OFF)
OV/UV Fault
V
SHDN Threshold Voltage
SHDN(THR)
V
SHDN, EN Threshold Hysteresis
SHDN_EN(HYS)
I
SHDN, EN Pull-Up Current
SHDN_EN
V
OV1 to O3, UV1 to UV3 Comparator
OV_UV(THR)
Threshold
V
OV1 to O3, UV1 to UV3 Comparator
OV_UV(HYS)
Hysteresis
t
V1 to V3 Validation Time
VALID
V1
Operating Voltage of Channel V1
V2
Operating Voltage of Channel V2
V3
Operating voltage of Channel V3
I
Load Current
LOAD
AVI
Auxiliary Voltage Input
DEMO MANUAL DC1717A
Prioritized PowerPath™ Controller
LTC
4417
to
enabled and powers the load. Two or more LTC4417s
®
can be cascaded to provide switchover between more
than three rails.
Design files for this circuit board are available at
http://www.linear.com/demo/DC1717A
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
PowerPath is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
Specifications are at T
A
CONDITIONS
V
= 11V, G1 to G3 = Open
OUT
V
= 11V, I = –10µA
OUT
V
= 11V, I = 10µA
OUT
V1 = V2 = V3 = 2.8V, V
= 2.6V, G1 to G3 Rising Edge
OUT
V
= 11V, C
= 10nF
OUT
GATE
V
= 11V, C
= 10nF
OUT
GATE
V
= 2.6V, V1 to V3 = 2.8V, (G1 to G3) = ΔV
OUT
Measure (V1 to V3) – V
, V
OUT
OUT
V
= 11V, C
= 10nF
OUT
GATE
I = 1mA, (V1 to V3) = 2.5V, V
OUT
SHDN Rising
SHDN = EN = 0V
V
= 11V, OV1 to OV3 Rising, UV1 to UV3 Falling
OUT
V
= 11V
OUT
= 25°C
MIN
2.5
5.4
5.8
4.5
0.12
4
7.5
+ 300mV
0.8
G
Falling
30
0.7
= 0V
5
0.4
–0.5
0.985
15
100
9.6
4
6.4
6
LTC4417
TYP
MAX
UNITS
36
V
6.2
6.7
V
6.6
7
V
5.2
6
V
0.35
0.6
V
9
20
V/µs
13
22
V/µs
2
7
µA
120
200
mV
2
3
µs
0.2
0.55
V
8
13
µs
0.8
1.2
V
100
mV
–2
–5
µA
1
1.015
V
30
45
mV
256
412
ms
12
14.4
V
5
6
V
8
9.6
V
2
A
24
V
dc1717afa
1
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Table of Contents
Summary of Contents for Linear DC1717A
- Page 1 If the highest priority rail voltage falls out of the defined window (overvoltage or undervoltage), L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and PowerPath is a trademark of Linear Technology Corporation. All other trademarks are the the rail with the next highest priority, which is valid, is property of their respective owners.
-
Page 2: Operating Principles
V1, V2, and V3 voltages. regulated by an LT3060 (U4) to 5V. This auxiliary 5V rail DC1717A is designed to operate from inputs of 12V, also powers 100kΩ pull-ups for VALID pins. AVI must be 5V, and 8V, applied to V1, V2 and V3 respectively. The present in order for the board to operate. -
Page 3: Design Procedure For Modification Of Dc1717A
47µF during transient, and the value of load capacitance. Figure 1 Design proceDure for moDification of Dc1717a The valid input range for any supply is controlled by the The slew rate of the output voltage can be expressed as OV and UV comparators with resistive dividers (R4-R13). - Page 4 DEMO MANUAL DC1717A Design proceDure for moDification of Dc1717a The second summand, t , should be taken into As shown in the equation (3), the use of external slew rate pVALID(OFF) account if the associated LTC4417 input does not have...
- Page 5 LEDs and pull ups. Use this turret to verify that 5V CAS: used to cascade a second DC1717A. Connect the is present. CAS turret of the high priority DC1717A to the EN turret of the lower priority DC1717A. Grounds must be connected in common.
-
Page 6: Quick Start Procedure
Connecting the auxiliary power source (6V to 24V) to Placing the jumper JP2 (EN) in the ON position turns on the DC1717A (AVI and GND turrets) lights the green LED the LTC4417 powering the load with 12V (2.0A). In an... -
Page 7: Parts List
DEMO MANUAL DC1717A parts list ITEM REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER C1, C3, C5, C8 CAP., 1206 C2, C4, C6, C9 CAP., 2220 CAP., ALUM., 47µF 50V 20% SMT SUN ELECT., 50CE47BS C10, C11, C12, C13, C15 CAP., X5R, 1µF 50V, 10%, 0603 MURATA, GRM188R61H105KAALD CAP., X5R 10µF 10V 20% 0805... - Page 8 DEMO MANUAL DC1717A schematic Diagram dc1717afa...
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Page 9: Schematic Diagram
Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. - Page 10 Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions: This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety measures typically found in finished commercial goods.