Datasheet

MAX17117 Evaluation Kit
Evaluates: MAX17117
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*Default position.
Quick Start
Recommended Equipment
• 2.3Vto5.5V,2ADCpowersupply
• Voltmeters
Procedure
The MAX17117 EV kit is fully assembled and
tested. Follow the steps below to verify board operation.
Caution: Do not turn on the power supply until all
connections are completed.
1) Verify that a shunt is installed across pins 1-2 of
jumper JU1.
2) Verify that SW1 DIP switches are in the off position.
3) Connect the positive terminal of the power supply
to the VIN pad. Connect the negative terminal of the
power supply to the PGND pad. Set VIN to +3V.
4) Turn on the power supply and verify that the step-up
switching regulator output (VMAIN) is +8.5V.
5) Verify that the gate-on supply (GHON) is approxi-
mately +23V.
6) Verify that the gate-off supply (VGL) is approximately
-6V.
7) Verify that the output of the high-speed op amp
(VOUT) is approximately +4.25V.
8) Verify that the outputs of the high-voltage scan-driver
outputs are approximately -6V (= VGL).
Detailed Description of Hardware
The MAX17117 EV kit contains a step-up switching
regulator, a positive two-stage charge pump, a negative
single-stage charge pump, a high-speed op amp, and a
high-voltage, level-shifting scan driver with gate-shading
control. The EV kit operates from a DC power supply
between +2.3V and +5.5V.
As configured, the step-up switching regulator (VMAIN)
generates a +8.5V output and provides at least 250mA
from a +2.7V input. The step-up switching-regulator
output voltage can be adjusted up to +15V with different
feedback resistors (see the Output-Voltage Selection
section).
The GHON consists of two positive charge-pump stages
to generate approximately +23V and provides up to
20mA. The VGL consists of a single negative charge-
pump stage configured with a shunt zener diode to
generate approximately -6V and provides up to 10mA.
Loading GHON and VGL reduces the available VMAIN
current proportionally.
The op-amp output (VOUT) is fixed to +4.25V or can be
reconfigured to other voltages with changes to the volt-
age-divider resistors (see the Output-Voltage Selection
section).
The high-voltage, level-shifting scan driver with gate-
shading control is designed to drive the TFT panel gate
drivers. Its seven outputs swing 40V (max) between
+35V (max) and -15V (min) and swiftly drives capaci-
tive loads. The driver outputs (STH, CKH1–CKH6) swing
between their power-supply rails (GHON and VGL)
according to the input logic levels on their correspond-
ing inputs (ST, CK1–CK6) except during a gate-shading
period. During a gate-shading period, a CKH_ output
driver becomes high impedance, and an internal switch
connected between the CKH_ output’s capacitive load
and either RO or RE closes whenever the state of its cor-
responding CK_ input is logic-low. This allows a portion
of an output’s GHON-to-VGL transition to be completed
by partially discharging its capacitive load through an
external resistor attached to either RO or RE, for a dura-
tion set by the gate-shading period.
For further details, refer to the High-Voltage Scan Driver
section in the MAX17117 IC data sheet.
P1 provides an easy interface to connect external
circuitry containing the ST and CK1–CK6 logic signals
to the EV kit. When driving the ST and CK1–CK6 logic
signals through P1, place all SW1 switches in the on
position.
Table 1. Jumper JU1 Functions
SHUNT POSITION ENA PIN EV KIT OUTPUTS
1-2 ENA connected to LDOO through resistor R8
Outputs enabled
(VMAIN = +8.5V)
2-3 ENA connected to ground
Outputs disabled
(VMAIN ~ VIN)