background image

1

dc1717afa

DEMO MANUAL DC1717A

Description

LTC4417 

Prioritized PowerPath™ Controller 

Demonstration circuit DC1717A uses the 

LTC

®

4417

 to 

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 

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.

performance summary

Specifications are at T

A

 = 25°C

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

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

V1-V3, V

OUT

V1 to V3, V

OUT

 Operating Supply Range

2.5

36

V

ΔV

G

Open (VS-VG) Clamp Voltage 

V

OUT

 = 11V, G1 to G3 = Open  

5.4

6.2

6.7

V

ΔV

G(SOURCE)

Sourcing (VS-VG) Clamp Voltage

V

OUT

 = 11V, I = –10µA

5.8

6.6

7

V

ΔV

G(SINK)

Sinking (VS-VG) Clamp Voltage 

V

OUT 

= 11V, I = 10µA 

4.5

5.2

6

V

ΔV

G(OFF)

G1 to G3 Off (VS-VG) Threshold

V1 = V2 = V3 = 2.8V, V

OUT 

= 2.6V, G1 to G3 Rising Edge

0.12

0.35

0.6

V

ΔV

G(SLEW,ON)

G1 to G3 Pull-Down Slew Rate

V

OUT 

= 11V, C

GATE

 = 10nF 

4

9

20

V/µs

ΔV

G(SLEW,OFF)

G1 to G3 Pull-Up Slew Rate

V

OUT

 = 11V, C

GATE

 = 10nF

7.5

13

22

V/µs

I

GATE(LOW)

G1 to G3 Low Pull-Down Current

V

OUT

 = 2.6V, V1 to V3 = 2.8V, (G1 to G3) = ΔV

G

 + 300mV

0.8

2

7

µA

V

REV

Reverse Voltage Threshold 

Measure (V1 to V3) – V

OUT

, V

OUT

 Falling 

30

120

200

mV

t

G(SWITCHOVER)

Break-Before-Make Time

V

OUT

 = 11V, C

GATE

 = 10nF

0.7

2

3

µs

V

VALID(OL)

VALID1

 to 

VALID3

 Output Low Voltage

I = 1mA, (V1 to V3) = 2.5V, V

OUT

 = 0V

0.2

0.55

V

t

PVALID(OFF)

VALID1

 to 

VALID3

 Delay OFF from  

OV/UV Fault

5

8

13

µs

V

SHDN

(THR)

SHDN

 Threshold Voltage

SHDN

 Rising

0.4

0.8

1.2

V

V

SHDN

_EN(HYS)

SHDN

, EN Threshold Hysteresis

100

mV

I

SHDN

_EN

SHDN

, EN Pull-Up Current

SHDN

 = EN = 0V

–0.5

–2

–5

µA

V

OV_UV(THR)

OV1 to O3, UV1 to UV3 Comparator 

Threshold

V

OUT

 = 11V, OV1 to OV3 Rising, UV1 to UV3 Falling

0.985

1

1.015

V

V

OV_UV(HYS)

OV1 to O3, UV1 to UV3 Comparator 

Hysteresis

V

OUT

 = 11V 

15

30

45

mV

t

VALID

V1 to V3 Validation Time

100

256

412

ms

V1

Operating Voltage of Channel V1

9.6

12

14.4

V

V2

Operating Voltage of Channel V2

4

5

6

V

V3

Operating voltage of Channel V3

6.4

8

9.6

V

I

LOAD

Load Current

2

A

AVI

Auxiliary Voltage Input

6

24

V

Summary of Contents for DC1717A

Page 1: ...G SOURCE Sourcing VS VG Clamp Voltage VOUT 11V I 10µA 5 8 6 6 7 V ΔVG SINK Sinking VS VG Clamp Voltage VOUT 11V I 10µA 4 5 5 2 6 V ΔVG OFF G1 to G3 Off VS VG Threshold V1 V2 V3 2 8V VOUT 2 6V G1 to G3 Rising Edge 0 12 0 35 0 6 V ΔVG SLEW ON G1 to G3 Pull Down Slew Rate VOUT 11V CGATE 10nF 4 9 20 V µs ΔVG SLEW OFF G1 to G3 Pull Up Slew Rate VOUT 11V CGATE 10nF 7 5 13 22 V µs IGATE LOW G1 to G3 Low ...

Page 2: ...sis is 6 and can be changed to 3 by moving the JP1 jumper to the 30mV position The controller s break before make switching method prevents cross conduction between input channels and reversecurrentfromtheoutputcapacitorintotheselected input supply Each channel s control circuit of the LTC4417 has a REV comparator which monitors the connecting input supply and output load voltage The REV comparato...

Page 3: ... VALID pins at 0 7V but otherwise leaves the LTC4417 operating autonomously The following design considerations and equations dem onstrate the interrelation of the main component values and transient parameters in the rail transitions when the output voltage exceeds 0 7V The variables CS and RS used in the design equations correspond to the following board components C20 R23 for V1 12V channel C21...

Page 4: ...e Use CL INIT and RS No Is recalculated CL lower than initial CL INIT As shown in the equation 3 the use of external slew rate control will add additional delay to the total switchover time Unfortunately the actual components cannot be chosen until the load capacitance is known This circular issue can only be resolved through an iterative process TheprocessstartsbycalculatingtheCLOAD MIN assuming ...

Page 5: ...nal to the LTC4417 Optional R33 may be added as a pull up to the auxiliary 5V power supply SHDN pulled up by 2μA internal to the LTC4417 Optional R36 may be added as a pull up to the auxiliary 5V power supply CAS used to cascade a second DC1717A Connect the CAS turret of the high priority DC1717A to the EN turret of the lower priority DC1717A Grounds must be connected in common JP1 HYS Add 30mV fi...

Page 6: ... 30W to the DC1717A output turret or banana jack VOUT Do not use an electronic load in constant current mode Turn on three power supplies No additional LEDs should light Change the jumper JP3 SHDN header position from OFF to ON Three LEDs VALID1 VALID2 and VALID3 validating the input rail voltages should light Placing the jumper JP2 EN in the ON position turns on the LTC4417 powering the load with...

Page 7: ...Q3 DUAL P CHAN 40V POWERPAK1212 8 DUAL VISHAY Si7905DN T1 GE3 19 0 Q4 Q5 Q6 Q7 Q8 Q9 MOSFET P CHAN 40V FDD4685 DPAK OPT 20 1 Q10 XTOR N CHAN SOT23 DIODE INC MMBTA42 7 F 21 1 Q11 XTOR N CHAN SOT23 DIODE INC MMBT3904 7 F 22 1 R4 RES CHIP 1 69M 0 125W 1 0805 VISHAY CRCW08051M69FKEA 23 3 R5 R8 R12 RES CHIP 69 8k 0 125W 1 0805 VISHAY CRCW080569K8FKEA 24 3 R6 R9 R13 RES CHIP 130k 0 125W 1 0805 NIC NRC10...

Page 8: ...ROPRIETARY TO LINEAR TECHNOLOGY AND SCHEMATIC SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS SCALE NONE www linear com 3 DEMO CIRCUIT 1717A Thursday July 23 2015 1 2 PRIORITIZED POWERPATH CONTROLLER N A LTC4417CUF KIM T VLAD O SIZE DATE IC NO REV SHEET OF TITLE APPROVALS PCB DES APP ENG TECHNOLOGY Fax 408 434 0507 Milpitas CA 95035 Phone 408 432 1900 1630 McCarthy Blvd LTC Confidential For Customer...

Page 9: ...APPLICATION COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SCHEMATIC SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS SCALE NONE www linear com 3 DEMO CIRCUIT 1717A Thursday July 23 2015 2 2 PRIORITIZED POWERPATH CO...

Page 10: ...INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE EXCEPT TO THE EXTENT OF THIS INDEMNITY NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES The user assumes all responsibility and liability for proper and safe handling of the goods Further the user releases LTC from all claims arising from the handling or use of the...

Page 11: ...Mouser Electronics Authorized Distributor Click to View Pricing Inventory Delivery Lifecycle Information Analog Devices Inc DC1717A ...

Reviews: