DC1463A-B - LINEAR TECHNOLOGY

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DESCRIPTION

Demonstration Circuit DC1463A is a Switching Power Manager with USB On-the-Go and Overvoltage Protection

featuring the LTC®4160.

PERFORMANCE SUMMARY

Specifications are at T

A

= 25°C

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

VBUS

Bus Input Voltage Range 4.35 6 V

V(LDO3V3) 3.3V LDO Output VOUT > 3.5V 3.1 3.4 V

V(BAT)

Battery Float Voltage LTC4160 Constant Voltage Mode

LTC4160-1 Constant Voltage Mode

4.15

4.05

4.23

4.13

V

I(BAT)

Battery Charge Current Constant Current Mode, R

PROG

= 2.00k



485 515 mA

VOUT

Output Voltage ILIM[1..0] = 01b, I(VOUT) ≤ 1.25A, V(BAT) > 3.6V

I(VOUT) ≤ 1.25A, V(BAT) < 3.6V

V(BAT)

3.6V

VBAT + 0.45V V

V

OTG

VBUS voltage in OTG mode I(VBUS) ≤ -500mA 4.5 5 5.5 V

QUICK START PROCEDURE

Refer to Figure 1 for the proper measurement

equipment setup and jumper settings and follow the

procedure below.

NOTE.

When measuring the input or output voltage ripple, care

must be taken to avoid a long ground lead on the oscilloscope

probe. Measure the input or output voltage ripple by touching the

probe tip directly across the VBUS or VOUT(x) and GND terminals.

See Figure 2 for proper scope probe technique.

1. Set all jumpers as shown in Figure 1 and LD1 =

0A, PS1 = 5V, LD2 = 0A, LD3 = 0A, PS2 = 3.6V.

Observe VOUT (VM4), LDO3V3 (VM3), and

V(NTC) (VM2). The LTC4160 is operating as

USB power manager. The current from PS1 will

try to be the charging current * (3.6V/5V), or ap-

proximately 400mA, but will be limited by the in-

put current limiter to ~ 100mA.

2. Increase LD3 to 80mA, and LD2 to 25mA. Ob-

serve VOUT(VM4), I(VUSB) (AM1) and LDO3V3

(VM3). Set LD2 to 0A. The loads on VOUT and

LDO3V3 are now reducing the charge current

further.

3. Increase LD3 to 250mA. Observe VOUT(VM4),

I(VUSB) (AM1). The load on VOUT will engage

the input current limit, and VOUT will drop until

the ideal diode engages to provide the difference

current.

DEMO CIRCUIT 1463

A

QUICK START GUID

E

LTC4160EPDC / LTC4160EPDC-1

Switching Power Manager with USB

On-the-Go and Overvoltage Protection

LTC4160EPDC/LTC4160EPDC-1

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4. Change JP1 & JP2 to ‘1’. Observe VOUT(VM4)

and I(VUSB) (AM1). The input current limit is

now 500mA, and the load on VOUT is 250mA, so

the battery charge current will be approximately

250mA.

5. Increase LD3 to 750mA. Observe VOUT(VM4)

and I(VUSB)(AM1). The load on VOUT again ex-

ceeds the input current limit and the VOUT volt-

age will drop until the ideal diode turns on and

supplies current from the battery.

6. Change JP1 to ‘0’. Observe VOUT(VM4) and

I(VUSB) (AM1). The input current limit is now

1A, and the battery is charging at 250mA. VOUT

is loaded at 750mA, so only the remaining cur-

rent is available to charge the battery.

7. Increase LD3 to 1.25A. Observe VOUT(VM4)

and I(VUSB) (AM1). Set LD3 to 0A. Observe

I(BAT) (AM4).The input current limit is activated

and VOUT will drop until the ideal diode turns on.

8. Increase PS2 until I(BAT) is less than 25mA.

Observe V(BAT) (VM5). Set PS2 to 3.6V.

9. Disconnect PS1. Change JP3 (ENOTG) to ‘ON’.

Observe VUSB (VM1) and V(CLPROG)(VM6).

Although PS1 is disconnected, the USB On-The-

Go mode is enabled, and the LTC4160 is provid-

ing VUSB from the battery.

10. Increase LD1 to 500mA. Observe VUSB(VM1)

and V(CLPROG)(VM6). In On-The-Go mode the

LTC4160 can provide 500mA of output current

on the USB.

11. Reset the Jumpers to their default position.

LTC4160EPDC/LTC4160EPDC-1

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Figure 1. Proper Measurement Equipment Setup for DC1463A

VIN

GND

Figure 2. Measuring Input or Output Ripple

LTC4160EPDC/LTC4160EPDC-1

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Figure 3. Circuit Schematic

LTC4160EPDC/LTC4160EPDC-1

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Figure 4. Bill of Materials