Rainbow Electronics MAX17117 User Manual
Page 16
Internal-Switch Boost Regulator with Integrated
7-Channel Scan Driver, Op Amp, and LDO
MAX17117
16 _____________________________________________________________________________________
If the gate-shading control is enabled, a gate-shading
period is initiated by a falling edge of a CK_ input when-
ever V
DTS
is less than 100mV. Once the gate-shading
period is initiated, a switch across C
SET
(S
DTS
) opens,
allowing C
SET
to be charged through R
SET
. Once V
DTS
reaches 1.24V, S
DTS
closes to discharge C
SET
, the
gate-shading period is terminated, and the CKH_ output
states are directly determined by their corresponding
CK_ input logic states again. Once a gate-shading
period is initiated, V
DTS
must charge to 1.24V and sub-
sequently discharge back below 100mV, before the next
CK_ falling can activate a new gate-shading period.
By configuring R
SET
and C
SET
as shown in Figure 1, the
gate-shading period time duration is determined by R
SET
and C
SET
and V
LDOO
(see the Setting the Gate-Shading
Period Time Duration section). The gate-shading control
can be disabled by removing R
SET
. If R
SET
is removed,
the states of the CKH_ outputs are always determined by
their corresponding CK_ input logic states. See Figure 5.
Low-Dropout Linear Regulator (LDO)
The MAX17117 has an integrated 0.8I pass element
and can provide at least 350mA. The output voltage is
accurate within Q1%.
Thermal-Overload Protection
When the junction temperature exceeds T
J
= +170NC
(typ), a thermal sensor activates a fault-protection latch,
which shuts down all outputs, allowing the IC to cool
down. All outputs remain off until the IC cools and the
input voltage is cycled below, then back above the IN
UVLO threshold.
The thermal-overload protection protects the IC in the
event of fault conditions. For continuous operation, do
not exceed the absolute maximum junction temperature
rating of T
J
= +150NC.
Figure 4. Scan-Driver Block Diagram
CKH1
CKH3
CKH5
S1
S3
S5
RO
S
DTS
C
SET
R
O
R
SET
LDO
LDOO
CK1
CK2
CK3
CK4
CK5
CK6
LEVEL SHIFTER
AND
GATE-SHADING
LOGIC
DTS
CKH2
CKH4
CKH6
S2
S4
S6
RE
R
E
MAX17117