MAX77301 Evaluation Kit
Evaluates: MAX77301
General Description
The MAX77301 evaluation kit (EV kit) is a fully assembled
and tested PCB for evaluating the MAX77301 dual-path
lithium-ion (Li+) battery charger with USB enumeration
and automatic adapter-type detection features. The EV
kit is powered from a USB port or dedicated charger with
automatic detection of adapter type and USB enumera-
tion capability.
The IC features a Smart Power Selector™ feature that
makes the best use of limited USB or adapter power.
Battery charge current is set independent of the input-
current limit. Power not used by the system charges the
battery. This allows the application to operate without a
battery, discharged battery, or dead battery. Automatic
input selection switches the system between battery,
battery assist, and external power modes.
The EV kit provides LED indicators for adapter-type
detection (UOK), external power-on (EXT_PWRON),
charging status (CHG_STAT), external power-source
current capability (CHG_TYPE), and interrupts (IRQ).
The EV kit also features an NTC thermistor for thermal
protection and JEITA-compliant* charging.
The EV kit is configured for full-speed USB by default,
but can be configured for low-speed USB by removing
the crystal oscillator and adjusting jumper default settings
(see
Table 1).
Benefits and Features
●
Enables Charging from a Micro-B USB Connector
●
USB Enumeration without Host-Processor
Intervention
●
Automatic Detection of Adapter Type or USB Port
●
Dual-Speed USB Operation (Full Speed or
Low Speed)
●
Input Overvoltage Protection to 16V
●
Smart Power Selector
• Automatic Current Sharing Between Battery
Charging and System
• Operates with Discharged or No Battery
●
LED Indicators
●
NTC Monitoring of Battery Temperature
●
JEITA-Compliant Charging Profile
●
Thermal-Charge Regulation Prevents the IC from
Overheating
Ordering Information
appears at end of data sheet.
Smart Power Selector is a trademark of Maxim Integrated
Products, Inc.
*U.S.
Patent # 6,507,172.
19-8646; Rev 0; 2/17
MAX77301 Evaluation Kit
Evaluates: MAX77301
Quick Start
Recommended Equipment
●
MAX77301 EV kit test fixture
●
USB A-to-USB micro-B cable (supplied with the EV kit)
●
User-supplied PC with a spare USB port
●
I
2
C command module (CMAXQUSB or MINIQUSB)
(USB cable included)
●
Four digital multimeters with current-measurement
capability (DMM1–DMM4)
●
BAT electronic load (constant voltage (CV), able to
sink current) or Li+ battery
●
SYS electronic load
●
MAX77301 software (GUI)
Note:
In the following sections, software-related items are
identified by bolding. Text in
bold
refers to items directly
from the EV system software. Text in
bold and under-
lined
refers to items from the Windows operating system.
5)
4)
3)
same link. The EV kit is compatible with both the
CMAXQUSB and MINIQUSB interface boards.
Install the EV kit software and USB interface firm-
ware inside the temporary folder on your PC by run-
ning the .EXE program.
Connect the USB cable from the PC to the CMAX-
QUSB/MINIQUSB interface board. A
Building
Driver
Database
window pops up in addition to a
New Hardware Found
message when installing
the USB driver for the first time. If you do not see
a window that is similar to the one described above
after 30s, remove the USB cable from the board and
reconnect it. Administrator privileges are required to
install the USB device driver on Windows
®
.
Follow the directions of the
Add New Hardware
Wizard
to install the USB device driver. Choose the
Search for the best driver for your device
option.
Specify the location of the device driver (default in-
stallation directory) using the
Browse
button. Dur-
ing device driver installation, Windows may show a
warning message indicating that the device driver
that Maxim uses does not contain a digital signature.
This is not an error condition and it is safe to proceed
with installation. Refer to the USB_Driver_Help.PDF
document for additional information.
If using the CMAXQUSB command module, ensure
that the shunt on jumper JU1 is in the 3.3V position.
Carefully connect the boards by aligning the 20-pin
connector on the EV kit with the 20-pin header on
the CMAXQUSB/MINIQUSB interface board. Gently
press them together.
Procedure
The EV kit is a fully assembled and tested surface-mount
board. Follow the steps below and
Figure 9
to set up and
verify the IC and board operation:
1)
2)
Verify that the jumpers on the EV kit are properly
configured, as shown in
Table 1.
Visit
www.maximintegrated.com/evkitsoftware
to
download the latest version of the EV kit software.
Save the EV kit software to a temporary folder
and uncompress the ZIP file. The CMAXQUSB or
MINIQUSB firmware can also be found at the
6)
7)
Table 1. Default Jumper Settings (JU1–JU10)
JUMPER
JU1
JU2
JU3
JU4
JU5
JU6
JU7
JU8
JU9
JU10
SHUNT POSITION
PCB short
PCB short
PCB open
1-3
PCB short
1-2
1-2
1-2
1-2
PCB open
Connects XIN to the Y1 crystal.
Connects XOUT to INT_3V3.
Selects BUS, SYS, or V
DD
as the LED indicator power source.
Shorts DGND and AGND together. Do not disconnect.
Selects the logic level for
ENU_EN_HW.
Selects the logic level for
STDB_EN_HW.
Selects the logic level for CEN.
Selects the logic level for IBUS_DEF.
Connects XIN to AGND.
FUNCTION
Connects XOUT to the Y1 crystal.
Windows is a registered trademark and registered service mark of Microsoft Corporation.
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MAX77301 Evaluation Kit
Evaluates: MAX77301
8)
9)
If simulating a battery, set the BAT electronic load to
3.6V at CV mode and turn off.
Observe correct polarity. Connect the BAT electronic
load/Li+ battery and series digital multimeter (DMM4)
in the current-measurement mode, as shown in
Figure
9.
Leave the BAT electronic load turned off. If using an
Li+ battery, leave the positive terminal unconnected.
23) Turn on the SYS electronic load and verify that the
voltage read by DMM3 is (DMM1 + 140mV) or 4.3V,
whichever is greater.
24) Disconnect the BAT electronic load/Li+ battery
and wait until DMM1 reads 4.2V, indicating a fully
charged battery.
25) Verify that the voltage read by DMM3 is the greater
of (DMM1 + 140mV) or 4.35V.
26) Turn off the SYS electronic load.
27) Remove the USB cable from P1.
28) Disconnect all test leads from the EV kit.
10) Connect DMM1 across the BAT electronic load/Li+
battery. Connect the positive terminal of DMM1 to
the positive terminal of the Li+ battery. Connect the
negative terminal of DMM1 to the negative terminal
of the Li+ battery.
11) Connect DMM2 from INT_3V3 to BUS_DGND.
12) Connect DMM3 from SYS to SYS_DGND.
13) Preset the SYS electronic load for 100mA and turn off.
14) Connect the SYS electronic load from SYS to
SYS_GND.
15) Plug a USB cable from P1 to the PC with a 500mA
USB cable.
16) Verify that the LED at D1 is on, indicating that a
dedicated charger has been detected.
17) Start the EV kit software.
18) Select the
Device
menu item in the upper-left corner,
then
Connect.
Wait for the device to respond, and in
the
Synchronize
window, press the
Read and Close
button. Normal device operation is verified when
Connected
is displayed in bottom-left corner.
Note:
All default EV kit software settings are used
for the remainder of the test procedure.
19) Turn on the BAT electronic load or connect the posi-
tive terminal of the Li+ battery to V
BAT+
.
Note:
When using an Li+ battery, if V
BAT+
< 2.5V,
the charger starts up in precharge mode. If V
BAT+
≥ 2.5V, the charger starts up in fast-charge mode.
If in precharge mode, verify that DMM4 reads 50mA. If
in fast-charge mode, verify that DMM4 reads 200mA.
20) Verify that
CHG_STAT
(the LED at D4) is on, indicat-
ing that charging is occurring.
21) Verify that the voltage read by DMM2 is approxi-
mately 3.3V.
22) Verify that the voltage read by DMM3 is (DMM1 +
140mV) or 4.3V, whichever is greater.
Detailed Description of Hardware
The MAX77301 EV kit evaluates the MAX77301 inte-
grated 1-cell Li+ charger with USB enumeration and
adapter-type detection capability. The EV kit negotiates
charging current from the USB host or hub, without pro-
cessor intervention. The IC also automatically detects for
a dedicated charger, USB charger, or adapter and sets
the input-current limit accordingly. The USB input power
not used by the system charges the battery.
USB Interface
An integrated USB peripheral controller provides
autoenumeration for full-speed and low-speed modes.
The USB controller is in charge of:
●
Executing adapter-detection sequence: Detects
what type of adapter is externally connected to the
USB receptacle (P1) and sets the input-current limit
accordingly.
If the USB receptacle (P1) is attached to a USB charger
(host or hub) or a USB 2.0 (host or hub), it enumerates
as an HID device and negotiates the maximum charging
current level (from BUS).
The IC operates in low-speed mode using an internal
6MHz oscillator and does not require an external crystal
to be USB compliant. The IC operates in full-speed mode
and requires an external 12MHz crystal (Y1,
Figure 9).
According to the USB 2.0 specification, a low-speed
device is not allowed to use a standard USB type-B
connector, which is why the IC is also able to operate in
full-speed mode. This makes it possible to use a custom or
captive cable for low-speed mode using the IC and still be
USB compliant. While operating in full-speed mode, using
the IC allows use of a standard USB type-B connector.
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MAX77301 Evaluation Kit
Evaluates: MAX77301
Adapter Detection
When an adapter is present on the USB receptacle (P1),
the IC examines the external device to identify the type of
adapter connected. The possible adapter types are:
●
Dedicated charger
●
USB charger (host or hub)
●
USB 2.0 low power (host or hub)
●
USB 2.0 high power (host or hub)
Each of these different devices has different current capa-
bility, as shown in
Table 2.
When an adapter is connected, the IC performs a series
of tests to identify the type of device connected. Refer to
the flow charts in the MAX77301 IC data sheet for more
details.
2)
3)
With the battery connected and no external power in-
put, the system is powered from the battery.
With an external power input connected and no
battery, the system is powered from BUS.
If the junction temperature starts to get too hot (110°C,
typ), the charging rate is reduced. If this is insufficient to
cool down the IC, the input-current limit is then reduced.
SYS Regulation Voltage
The IC always regulates SYS to 140mV (typ) above
BAT+, with a minimum voltage programmable from 3.4V
to 4.5V, regardless of what device is connected. The 3.4V
minimum voltage regulation reduces the ripple on SYS
during peak load conditions where the input-current limit
is tripped.
Smart Power Selector
The Smart Power Selector seamlessly distributes power
between the external adapter input (BUS), the battery
(BAT+), and the system load (SYS). The Smart Power
Selector basic functions are:
1)
With both an external adapter and battery connected:
a) When the system load requirements are less than
the input-current limit, the battery is charged with
residual power from the input.
b) When the system load requirements exceed the
input-current limit, the battery supplies supplemen-
tal current to the load.
BUS
Q1
BUS_DGND
CHARGE
CURRENT
LOAD
CURRENT
SYS
SYSTEM
LOAD
SYS_DGND
Q2 CHARGE
AND SYS LOAD
SWITCH
BAT+
1-CELL Li+
MAX77301
GND
BAT-
Figure 1. Smart Power Selector
Table 2. Adapter Types
ADAPTER TYPE
Dedicated charger
Charger
downstream port
Apple 500mA
Apple 1A
Apple 2A
Sony 500mA
Sony 500mA type B
USB 2.0 low power
USB 2.0 high power
OUTPUT VOLTAGE
4.75V to 5.25V at I
LOAD
< 500mA;
2.0V to 5.25V for I
LOAD
≥ 500mA
4.75V to 5.25V at I
LOAD
< 500mA;
2.0V to 5.25V for I
LOAD
≥ 500mA
4.75V to 5.25V at I
LOAD
< 500mA
4.75V to 5.25V at I
LOAD
< 1A
4.75V to 5.25V at I
LOAD
< 2A
4.75V to 5.25V at I
LOAD
< 500mA
4.75V to 5.25V at I
LOAD
< 500mA
4.25V to 5.25V
4.75V to 5.25V
OUTPUT CURRENT
500mA to 1.8A
500mA to 900mA for low-speed and full-speed operation;
500mA to 1.5A for low-speed and full-speed operation
500mA (max)
1A (max)
2A (max)
500mA (max)
500mA (max)
100mA (max)
500mA (max)
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MAX77301 Evaluation Kit
Evaluates: MAX77301
LED Indicators
UOK
Status Output
UOK
is an open-drain output that is pulled low when
the BUS input is inserted and adapter-type detection is
complete. In USB suspend mode, the
UOK
pin flashes
with a duty cycle of 50% for a duration of 1.5s. When
D+/D- open is detected and bit nENU_EN = 1,
UOK
flashes with a duty cycle of 50% for a duration of 0.15s.
UOK
is in high impedance if no adapter is detected.
The input UVLO/OVLO thresholds must be met prior to
adapter detect and
UOK
pin response. The UVLO/OVLO
thresholds are shown in
Table 3.
The
EXT_PWRON
output can be connected to an exter-
nal device that controls power to external circuits, such
as an external p-channel MOSFET. If a valid adapter is
connected to the system while the battery is below the
V
BAT_UVLO
threshold,
EXT_PWRON
transitions from
high impedance to low when the adapter type is deter-
mined and
UOK
transitions from high to low impedance.
Charge Status Output (CHG_STAT)
CHG_STAT
is an active-low, open-drain output indicat-
ing state-of-battery charging. A temperature or timer fault
changes the charge state of the
CHG_STAT
pin. See
Table 4
for
CHG_STAT
behaviors.
CHG_TYPE Status Output
CHG_TYPE is an open-drain output that indicates the
type and current limit of the external power supply. The
pin is pulled low to indicate a 100mA USB 2.0 host with
device input-current limit (ILIM) ≤ 100mA. CHG_TYPE is
high impedance when the device input-current limit (ILIM)
is ≥ 500mA.
Interrupt Request Output (IRQ)
IRQ
is an active-low, open-drain output that is pulled low
when an interrupt occurs. If an interrupt has occurred, the
event and status information is available in the EVENT_
and STATUS_ registers. Interrupts indicate temperature
and voltages as well as charge and timer fault conditions.
Events are triggered by a state change in the associated
register. The event registers are reset to the default condi-
tion when read by the I
2
C interface. When the EVENT_
registers are read in page mode, the
IRQ
is not released
until the last bit has been read. New interrupt events are
held until a complete read of all registers has occurred.
The interrupt mask bits located in register 0x07 disable
the output pin, maintaining a high-impedance state.
EXT_PWRON
Output
EXT_PWRON
is an active-low, open-drain output that is
pulled low after a valid external power supply is present.
If a valid power supply is not present,
EXT_PWRON
is in
high impedance.
Table 3. UVLO/OVLO Thresholds
FOR
Initial BUS detection
USB 2.0 low power
USB 2.0 high power, or when ILIM is not set to 111
Adaptive (when ILIM is set to 111)
UVLO
4.0V (typ) rising
3.9V (typ) falling
4.1V (typ) falling
V
SYS
+ 50mV (typ) falling
6.9V (typ) (V
BUS
rising)
OVLO
Table 4.
CHG_STAT
Indications
CHARGER STATUS
Charge in progress, low (continuous)
Charge suspend (due to temperature faults) pulses with 1.5s
duration and 50% duty cycle
Charge suspend (due to temperature faults) pulses with 1.5s
duration and 50% duty cycle
Timer fault pulses with 0.15s duration and 50% duty cycle
Charge done, high impedance
Battery removed pulses with 0.1s duration
CHG_STAT
BEHAVIOR
Charge in progress, low (continuous)
Charge suspend (due to temperature faults) pulses with 1.5s
duration and 50% duty cycle
Charge suspend (due to temperature faults) pulses with 1.5s
duration and 50% duty cycle
Timer fault pulses with 0.15s duration and 50% duty cycle
Charge done, high impedance
10% to 20% duty cycle
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