MAX6948B MAXIM [Maxim Integrated Products], MAX6948B Datasheet - Page 14

• Manufacturer Part Number: MAX6948B
• Description: High-Efficiency PWM LED Driver with Boost Converter and Five Constant-Current GPIO Ports
• Manufacturer: MAXIM [Maxim Integrated Products]

High-Efficiency PWM LED Driver with Boost
Converter and Five Constant-Current GPIO Ports
The MAX6948B contains five I/O ports (P0–P4). Configure
the five I/O ports as logic inputs, open-drain logic outputs,
or constant-current sinks in any combination. Table 7
provides a detailed description of the individual port con-
figuration registers. Use registers 0x00 to 0x04 to individu-
ally assign each port (see the PWM Intensity Control and
Table 7. Port Registers Format (0x00 to 0x04, 0x0A, 0x0B, and 0x0C)
14
Figure 1. Simplified Schematic of I/O Ports
Port is logic-low. Port is still active in shutdown mode.
Port is logic-high. Set this mode when using GPIO as an input.
Port is still active when in shutdown mode.
Port is a static constant-current sink. Port is high impedance
when in shutdown mode.
Port is a constant-current sink with a 3/256 duty cycle. Port is
high impedance when in shutdown mode.
Port is a constant-current sink with a 4/256 duty cycle. Port is
high impedance when in shutdown mode.
Port is a constant-current sink with a 5/256 duty cycle. Port is
high impedance when in shutdown mode.
Port is a constant-current sink with a 254/256 duty cycle. Port is
high impedance when in shutdown mode.
Power-up default setting (port is high impedance)
INTERFACE
REGISTER DESCRIPTION
TO/FROM
SERIAL
I/O Ports (P0–P4)
OUTPUT-CURRENT
GLOBAL-CURRENT
OUTPUT PORT
8-BIT LATCH
1-BIT LATCH
3-BIT LATCH
REGISTER
REGISTER
REGISTER
PORT COMMAND
READ I/O
MSB
CLOSE SWITCH: 0x02 TO 0xFE
POSITION A: 0x00 TO 0x01
POSITION B: 0x02 TO 0xFF
4-BIT DAC
U
U
U
GENERATOR
Phasing section). Use registers 0x0A, 0x0B, and 0x0C to
assign the same port setting to multiple ports (Table 1).
When powered off, the I/O ports remain in high impedance.
Figure 1 shows the I/O port structure of the MAX6948B.
I/O ports P0–P4 default to high impedance on power-up,
to prevent connected ports from drawing current. Ports
used as inputs do not load their source signals.
PWM
D7
0
0
0
0
0
0
1
1
CURRENT
ENABLE
D6
0
0
0
0
0
0
1
1
SET
D5
0
0
0
0
0
0
1
1
REGISTER DATA
D4
0
0
0
0
0
0
1
1
A
D3
0
0
0
0
0
0
1
1
n-CHANNEL
MOSFET
B
I/O PORT
D2
0
0
0
0
1
1
1
1
D1
0
0
1
1
0
0
1
1
D0
0
1
0
1
0
1
0
1