Detailed Description
The MAX17079 is a 7-channel level shifter that converts
a 2-bit logic-level input to a five-level high-voltage out-
put. The outputs are connected to the four output rails
(VH1, VH2, VL1, VL2) through 3Ω switches and to the
fifth rail (VCOM) through a 15Ω switch. The output rails
lie between DGND and the upper supply rail (VLS).
The MAX17079 has two modes of operation. When
ST = VCC, it operates in sequential mode and when ST
= AGND, it operates in combinational mode. The
MAX17079 can operate in either two-level output or
four-level output configuration. In four-level output
mode, the output can connect to VH1, VH2, VL2, or VL1,
and in two-level output mode, the output can connect to
VH2 or VL2. Connect CH to AGND for four-level opera-
tion and connect CH to VCC for two-level operation.
The output supply rail voltages should satisfy the fol-
lowing condition at all times:
VLS ≥ VH1 ≥ (VH2, VL2, VCOM) ≥ VL1
The MAX17079 has built-in dead time to avoid shoot-
through current. The propagation delay between input
and output is 80ns and the rise time is 30ns.
Figure 1 is the MAX17079 typical operating circuit and
Figure 2 shows the functional diagram.
Four-Level Combinational Logic
Connect CH and ST to AGND for four-level combina-
tional operation. If EN is LOW or VCC is less than UVLO
or VLS is less than its UVLO, the outputs are in STAND-
BY and the outputs connect to VCOM. After EN is HIGH
or VCC is greater than UVLO and VLS is greater than
its UVLO, the outputs are ready to respond to logic
inputs at Ax, Bx. If EN goes HIGH after a rising or
falling edge of Ax or Bx, the device remains in STAND-
BY state until the next edge comes. All state transitions
can be level triggered. The output is determined by the
following truth table (Table 1).
MAX17079
4-Level or 2-Level Logic to High-Voltage
Level Shifter for TFT LCD TV Display
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Pin Description (continued)
