MAX17010ETL+T Maxim Integrated Products, MAX17010ETL+T Datasheet - Page 14

• Manufacturer Part Number: MAX17010ETL+T
• Description: IC LCD DISPLAY BIAS 40-TQFN
• Manufacturer: Maxim Integrated Products

Specifications of MAX17010ETL+T

• Applications: LCD Monitor, Notebook Display
• Current - Supply: 50µA
• Voltage - Supply: 1.8 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 40-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The high-voltage, level-shifting scan drivers are
designed to drive the TFT panels with row-drivers inte-
grated on the panel glass. Its eight outputs swing from
+30V (max) to -6.3V (min) and can swiftly drive capaci-
tive loads. The typical propagation delays are 40ns,
with fast 16ns rise-and-fall times. The buffers can oper-
ate at frequencies up to 50kHz.
The thermal-overload protection prevents excessive
power dissipation from overheating the device. When
the junction temperature exceeds T
mal sensor immediately activates the fault protection,
which shuts down all outputs except VL, allowing the
device to cool down. Once the device cools down by
approximately 15°C, cycle the input voltage (below the
UVLO-falling threshold) to clear the fault latch and
reactivate the device.
The thermal-overload protection protects the controller in
the event of fault conditions. For continuous operation,
do not exceed the absolute maximum junction tempera-
ture rating of T
The minimum inductance value, peak current rating, and
series resistance are factors to consider when selecting
the inductor. These factors influence the converter’s effi-
ciency, maximum output-load capability, transient
response time, and output-voltage ripple. Physical size
and cost are also important factors to be considered.
The maximum output current, input voltage, output volt-
age, and switching frequency determine the inductor
value. Very high inductance values minimize the current
ripple and therefore reduce the peak current, which
decreases core losses in the inductor and I
the entire power path. However, large inductor values
also require more energy storage and more turns of wire,
which increase physical size and can increase I
in the inductor. Low inductance values decrease the
physical size but increase the current ripple and peak
current. Finding the best inductor involves choosing the
best compromise between circuit efficiency, inductor
size, and cost.
The equations used here include a constant (LIR),
which is the ratio of the inductor peak-to-peak ripple
current to the average DC inductor current at the full-
load current. The best trade-off between inductor size
and circuit efficiency for step-up regulators generally
has an LIR between 0.3 and 0.5. However, depending
on the AC characteristics of the inductor core material
Internal-Switch Boost Regulator with Integrated
High-Voltage Level Shifter and Op Amp
14
______________________________________________________________________________________
J
= +150°C.
Thermal-Overload Protection
Main Step-Up Regulator
Design Procedure
J
Inductor Selection
= +160°C, a ther-
2
R losses in
2
R losses
and ratio of inductor resistance to other power-path
resistances, the best LIR can shift up or down. If the
inductor resistance is relatively high, more ripple can
be accepted to reduce the number of turns required
and increase the wire diameter. If the inductor resis-
tance is relatively low, increasing inductance to lower
the peak current can decrease losses throughout the
power path. If extremely thin high-resistance inductors
are used, as is common for LCD panel applications, the
best LIR can increase to between 0.5 and 1.0.
Once a physical inductor is chosen, higher and lower
values of the inductor should be evaluated for efficiency
improvements in typical operating regions.
Calculate the approximate inductor value using the typi-
cal input voltage (V
(I
an appropriate curve in the Typical Operating
Characteristics , and an estimate of LIR based on the
above discussion:
Choose an available inductor value from an appropriate
inductor family. Calculate the maximum DC input cur-
rent at the minimum input voltage V
servation of energy and the expected efficiency at that
operating point (η
in the Typical Operating Characteristics :
Calculate the ripple current at that operating point and
the peak current required for the inductor:
The inductor’s saturation current rating and the
MAX17010’s LX current limit (I
and the inductor’s DC current rating should exceed
I
with less than 0.1Ω series resistance.
Considering the Typical Operating Circuit , the maximum
load current (I
and a typical input voltage of 3V. Choosing an LIR of 0.45
and estimating efficiency of 85% at this operating point:
IN(DC,MAX)
MAIN(MAX)
L
L
=
=
⎛
⎜
⎝
I
RIPPLE
8 5
⎛
⎜
⎝
), the expected efficiency (η
3
. For good efficiency, choose an inductor
I
.
V
IN DCMAX
V
MAIN
V
V
I
(
MAIN(MAX)
PEAK
IN
⎞
⎟
⎠
2
=
,
⎛
⎜
⎝
MIN
⎞
⎟
⎠
V
0 3
2
IN MIN
=
.
⎛
⎜
⎝
IN
8 5
) taken from an appropriate curve
I
)
(
IN DCMAX
I
A
MAIN MAX
.
=
), the maximum output current
(
) is 300mA, with an 8.5V output
×
L V
V
I
MAIN MAX
V
1 2
)
×
−
MAIN
.
V
,
×
(
IN MIN
3
MHz
(
MAIN
V
V
(
(
LIM
MAIN
)
−
)
+
⎞
⎟
⎠
×
) should exceed I
V
)
×
⎛
⎜
⎝
IN
I
)
f
RIPPLE
× η
OSC
0 85
f
×
−
OSC
0 5
.
IN(MIN)
2
.
V
V
MIN
IN MIN
MAIN
⎞
⎟
⎠
TYP
⎞
⎟ ≈
⎠
(
⎛
⎜
⎝
η
LIR
) taken from
3 6
TYP
)
. μ
using con-
)
⎞
⎟
⎠
H
PEAK