Datasheet

Evaluates: MAX8784
The MAX8784 features a HVS mode that can increase the
output voltages of the step-up switching regulator and the
positive charge pump to stress test the display panel dur-
ing production. The step-up switching-regulator’s output
is increased to +17V in HVS mode, set by resistor R21
(refer to the
HVS Mode section in the MAX8784 data
sheet). The positive charge-pump output is set to +30V in
HVS mode and is not adjustable.
Jumper Selection
Shutdown Mode (SHDN)
Jumper JU1 controls the shutdown pin (SHDN) of the
MAX8784 IC. The shutdown pin can also be controlled by
an external logic controller connected to the EV kit’s
SHDN pad. Remove the shunt from jumper JU1 before
connecting an external controller to the SHDN pad. See
Table 1 for shunt positions.
High-Voltage Switch Control (CTL)
Jumper JU2 configures the setting of the high-voltage
switch control pin (CTL) of the MAX8784 IC. The CTL pin
can also be controlled by an external logic controller con-
nected to the EV kit’s CTL pad. Remove the shunt from
jumper JU2 before connecting an external controller to
the CTL pad. See Table 2 for shunt positions.
VGON Discharge Path (DRN)
The MAX8784 EV kit features a method to configure the
VGON discharge path using resistor R19 and jumper
JU3. When CTL is low, GON connects to DRN, allowing
VGON to discharge through R19. R19 can be connect-
ed to AVDD or to PGND using jumper JU3. Table 3 lists
the selectable JU3 jumper options. If VGON’s desired
lower level is greater than AVDD, discharge VGON
toward AVDD to save power. VGON’s discharge rate
can be adjusted by selecting a different value for R19.
MAX8784 Evaluation Kit
4 _______________________________________________________________________________________
Table 1. JU1 Jumper Selection (SHDN)
SHUNT POSITION
SHDN PIN
CONNECTED TO
EV KIT FUNCTION
Installed* VIN Enabled
Not installed
GND (through
resistor R17)
Shutdown mode
None (external
logic controller
connected to
SHDN pad)
External logic
controller
SHDN driven by
external logic
controller. SHDN is
active-low.
* Default position.
Table 2. JU2 Jumper Selection (CTL)
SHUNT POSITION CTL PIN CONNECTED TO HIGH-VOLTAGE SWITCH CONFIGURATION
Installed VIN
GON pin connected to POUT pin
GON pin disconnected from DRN pin
Not installed* GND (through resistor R18)
GON pin connected to DRN pin
GON pin disconnected from POUT pin
None (external logic
controller connected to
CTL pad)
External logic controller
CTL driven by external logic controller
CTL high: GON pin connected to POUT pin
CTL low: GON pin connected to DRN pin
* Default position.
Table 3. JU3 Jumper Selection (DRN)
SHUNT POSITION
DRN PIN
CONNECTED TO
GON DISCHARGE
TOWARD
1-2*
AVDD (through
resistor R19)
AVDD
2-3
PGND (through
resistor R19)
PGND
* Default position.