Datasheet

Detailed Description of Hardware
The MAX17094 EV kit contains a high-performance
step-up switching regulator, a 250mA LDO, a positive
two-stage charge pump, a negative single-stage
charge pump, a high-speed op amp, and seven high-
voltage level-shifting buffers for scan-driver applica-
tions. The EV kit operates from a DC power supply
between +1.8V and +5.5V that provides at least 2A.
As configured, the step-up switching regulator (VMAIN)
generates a +8V output and provides at least 300mA.
The step-up switching-regulator output voltage can be
adjusted up to +14V with different feedback resistors
(see the
Output-Voltage Selection section).
The GON consists of two positive charge-pump stages
to generate approximately +21.5V and provides
up to 30mA. The GOFF consists of a single negative
charge-pump stage to generate approximately -6.5V
and provides up to 30mA. Loading GON and GOFF
reduces the available VMAIN current proportionally.
The op-amp output (VCOM) is SMBus programmable
and is configured for a +2.4V to +4V output-voltage
range. VCOM can source or sink peak current up to
150mA. The output-voltage range can be reconfigured
to other voltages with voltage-divider resistors R16 and
R17. Refer to the
Setting the VCOM Adjustment Range
section in the MAX17094 IC data sheet for more details.
The seven logic-level to high-voltage level-shifting
buffers can buffer seven logic inputs (A2–A8) and shift
them to a desired level (Y2–Y8) to drive TFT LCD row
logic. Each buffer outputs the voltage on the GOFF pin
(set through JU1) when its respective input is logic-low.
Each buffer (Y2–Y6) outputs the voltage-on GON1 (set
through JU3) when its respective input is logic-high.
Similarly, Y7 and Y8 output the voltage on GON2 (set
through JU4).
The seven switches within SW1 are used to select logic
levels on A2–A8 for testing purposes. Set each switch
open when driving A2–A8 with external logic. Use
jumpers JU14–JU18 to select between capacitive loads
on outputs Y2–Y8 and YDCHG for testing purposes.
GOFF Power Supply (JU1)
The MAX17094 EV kit incorporates jumper JU1 to pro-
vide an option to supply the gate-off (GOFF) supply.
GOFF can be supplied either through the on-board
negative charge pump (VN) or with an externally
applied voltage at the GOFF pad. See Table 1 for
jumper JU1 configuration.
Enable (JU2)
The MAX17094 EV kit incorporates jumper JU2 to
enable/disable the IC outputs. When EN is pulled low,
the DC-DC converter and op amp are disabled. The
high-voltage drivers and LDO will remain active if suffi-
cient voltage is available for operation. See Table 2 for
jumper JU2 configuration.
GON1, GON2 Power Supply (JU3, JU4)
The MAX17094 EV kit incorporates jumpers JU3 and
JU4 to provide an option to supply the gate-on (GON1,
GON2) supplies. GON1 and GON2 can be supplied
either through the on-board positive charge pump (VP)
or with an externally applied voltage at the respective
GON_ pad. See Table 3 for jumpers JU3 and JU4 con-
figuration.
Evaluates: MAX17094
MAX17094 Evaluation Kit
_______________________________________________________________________________________ 5
Table 1. Jumper JU1 Functions
SHUNT
POSITION
GOFF PIN
1-2*
Supplied on board through negative charge
pump (VN)
2-3 E xter nal user - sup p l i ed vol tag e ap p l i ed at GOFF p ad
* Default position.
Table 2. Jumper JU2 Functions
SHUNT
POSITION
EN PIN EV KIT OUTPUTS
Installed* Connected to VIN
Outputs enabled
(MAIN = +8V)
Not installed
Pulled to AGND
through R7
Outputs disabled
(MAIN ≈ VIN)
* Default position.
Table 3. Jumper JU3, JU4 Functions
SHUNT
POSITION
GON_ PIN
1-2*
Supplied on board through positive charge
pump (VP)
2-3
External user-supplied voltage applied at GON_
pad
* Default position.