QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1140A
HIGH EFFICIENCY USB POWER MANAGER PLUS 1A BUCK-BOOST CONVERTER
LTC3567EUF
5
QUICK START PROCEDURE
Complete the Quick Start Procedure outlined in the
Quick Start Guide for Demo Circuit 590 available
from the Linear Technology Web Site, prior to pro-
ceeding.
Using short twisted pair leads for any power connec-
tions, with all loads and power supplies off. Refer to
Figures 4 & 5 for the proper measurement and
equipment setup. 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 EN1 (JP1) to “OFF” and /CHRGEN (JP4) to
“Lo”. Set PS1 to 5V, and PS2 to 3.6V. Start the
GUI using QuickEval.
2. Observe that 95mA < I (VBUS) (AM1) < 100mA,
3.6V < VOUT(VM2) < 3.7V, 1.15V < V(CLPROG)
(VM6) < 1.2V. The default state of the USB input
current limit is 100mA, so although the charger
is calling for 500mA, the USB input current is
limited to 100mA. Consequent to this, VOUT
drops until the charger only draws 100mA.
3. Use the GUI to set the USB input current limit to
5X (500mA). Observer that 460mA < I(VBUS)
(AM1) < 500mA, 3.8V < VOUT (VM2) < 4.0V,
and 0.95V < V(PROG) (VM5) < 1.0V. The USB
current limit is now 500mA, so the charger can
now deliver the full charge current. VOUT is now
approximately equal to V(BAT) + 0.3V, and
V(PROG) is a the servo voltage of 1.0V.
4. Use the GUI to set the USB input current limit to
10X (1A). Observe that 460mA < I(VBUS) (AM1)
< 500mA, 3.8V < VOUT (VM2) < 4.0V, and 0.95V
< V(PROG) (VM5) < 1.0V. The USB current limit
is now 1A, so there is more than enough current
to operate the charger at 500mA.
5. Set PS1 to 0V, and Ld1 to 1A. Observe that 3.5V
< VOUT (VM2) <3.6V and V (VOUT, VBAT) <
200mV. The USB supply is off, and the only
source of energy is the battery. With VOUT
loaded at 1A, the ideal diode engages and energy
is routed from the battery to VOUT.
6. Set Ld1 to 400mA and PS1 to 5V. Observe that
3.8V < VOUT (VM2) < 4.0V. The USB current
limit is set to 1A, so both the charger load of
500mA, and 400mA into Ld1 can be supplied.
7. Set Ld1 to 0A, and use the GUI to enable
VOUT1. Observe that 3.8V < VOUT (VM2) <
4.0V and 3.25V < VOUT1 (VM4) < 3.35V. The
Buck-Boost regulator is now on, at no load.
The Buck-Boost regulator operates from VOUT.
8. Set Ld2 to 400mA. Observe 3.8V < VOUT
(VM2) < 4.0V, 3.25V < VOUT1 (VM4) < 3.35V.
The combined load of the charger and the load
on VOUT1, is still within the 1A current limit.
9. Use the GUI to turn off the battery charger, and
set Ld2 to 1A. Observe that 3.8V < VOUT (VM2)
< 4.0V, 3.25V < VOUT1 (VM4) < 4.0V. Because
the battery charger is off, the LTC3567 can sup-
ply 1A through the Buck-Boost regulator, and
stay within the 1A limit on USB current.
10. Set Ld2 to 0A, and use the GUI to turn on the
battery charger. Set NTC (JP3) to “EXT”. /CHRG
LED should flash.
11. Set NTC (JP3) to “INT” and EN1 (JP1) to “ON”.
Shut off all supplies and loads.
