MAX16805ATP+T Datasheet MAX16805ATP+T, MAX16806ATP+, MAX16806ATP+T | P13-P15

MAX16805/MAX16806

EEPROM-Programmable, High-Voltage, 350mA

LED Drivers with LED Current Foldback

______________________________________________________________________________________ 13

Message Format

Write to the MAX16805/MAX16806 by transmitting the

device’s slave address with R/W, 8th bit set to zero fol-

lowed by at least 1 byte of information (Figure 7). The

first byte of information is the command byte. The bytes

received after the command byte are the data bytes.

The first data byte goes into the internal register as

selected by the command byte (Figure 8). If there is

more than one data byte, the MAX16805/MAX16806

auto-increment to the next register address locations to

write the subsequent data bytes. The MAX16805/

MAX16806 auto-increment up to the register address

0x05, EEPROM Content Transfer register.

A read operation is performed as follows:

After the START condition (S), a 7-bit slave ID is sent

followed by an 8th bit (R/W) set to zero. A register

address is then sent to specify the address location

from which the read has to take place. To complete a

read operation, the master needs to generate a repeat-

ed START (Sr) followed by the 7-bit slave ID but with

the 8th bit (R/W) set to "1" this time indicating a read

operation. On the other hand, a read operation can be

performed by sending in the 7-bit slave ID followed by

an 8th bit (R/W) set to "1" if the current address location

happens to be the address location from which data

needs to be read.

ACKNOWLEDGE FROM

MAX16805/MAX16806

ACKNOWLEDGE FROM

MAX16805/MAX16806

SLAVE ADDRESS

COMMAND BYTE

Figure 7. Command Byte Received

ACKNOWLEDGE FROM

MAX16805/MAX16806

ACKNOWLEDGE FROM

MAX16805/MAX16806

ACKNOWLEDGE FROM

MAX16805/MAX16806

COMMAND BYTE

1 BYTE

DATA BYTESLAVE ADDRESS

Figure 8. Command and a Single Data Byte Received

ADDRESS

NO. OF BITS/

Binning Adjustment 0x00 4

Ramp Peak 0x01 3

LED Current Foldback

Threshold (LED_CFT)

0x02 4

Thermal Foldback Knee Point 0x03 4

Thermal Foldback Slope

Gain

0x04 2

Thermal Foldback Clamp

Level

0x05 3

EEPROM Content Transfer 0x06 —

EEPROM Program Enable 0x08 —

Password Register 0xFF —

Table 2. Registers Address

MAX16805/MAX16806

Binning Adjustment Register (0x00)

The Binning Adjustment register is a 4-bit register that

sets the differential regulation voltage reference

between CS+ and CS-. Only the first 4 bits of the data

byte update the Binning Adjustment register. The

remaining 4 bits are ignored. See Table 3. The factory-

default register value is 198mV.

Ramp Peak Register (0x01), MAX16806

The Ramp Peak register is a 3-bit register that sets the

maximum peak value of an internally 200Hz generated

ramp. The ramp signal can be programmed for a peak

value of 1.55V to 2.88V. Only the first 3 bits of the data

byte update the Ramp Peak register. The remaining 5

bits are ignored (see Table 4). The factory-default reg-

ister value is 2.88V.

LED Current Foldback Threshold

(LED_CFT) Register (0x02)

LED_CFT is a 4-bit register that sets the threshold for

the onset of the LED current foldback operation. Only

the first 3 bits of the data byte program the LED_CFT

rent foldback range.

The MAX16805/MAX16806 start dimming the LED cur-

rent when the input voltage exceeds the LED current

foldback threshold. For bit 3 = 0, the dimming range is

1.2 times the programmed ramp peak voltage. For bit 3

= 1, the dimming range is 2.4 times the programmed

ramp peak. To disable the LED current foldback feature

of the MAX16805/MAX16806 connect CFT to GND. The

factory-default register value is 16V.

EEPROM-Programmable, High-Voltage, 350mA

LED Drivers with LED Current Foldback

14 ______________________________________________________________________________________

REGULATION

VOLTAGE (mV)

BIT 3 BIT 2 BIT 1 BIT 0 HEX

103.0 0000(0x00)

109.0 0001(0x01)

115.4 0010(0x02)

121.8 0011(0x03)

128.2 0100(0x04)

134.6 0101(0x05)

141.0 0110(0x06)

147.4 0111(0x07)

153.7 1000(0x08)

160.1 1001(0x09)

166.5 1010(0x0A)

173.0 1011(0x0B)

179.3 1100(0x0C)

185.7 1101(0x0D)

192.1 1110(0x0E)

198.0 1111(0x0F)

Table 3. Binning Adjustment

RAMP END

POINT (V)

BIT 2 BIT 1 BIT 0 HEX

1.55 0 0 0 (0x00)

1.74 0 0 1 (0x01)

1.93 0 1 0 (0x02)

2.12 0 1 1 (0x03)

2.32 1 0 0 (0x04)

2.51 1 0 1 (0x05)

2.70 1 1 0 (0x06)

2.88 1 1 1 (0x07)

Table 4. Ramp Peak Value

CURRENT

FOLDBACK

THRESHOLD (V)

BIT 2 BIT 1 BIT 0 HEX

16.4 0 0 0 (0x00)

15.7 0 0 1 (0x01)

15.0 0 1 0 (0x02)

14.3 0 1 1 (0x03)

13.5 1 0 0 (0x04)

12.8 1 0 1 (0x05)

12.1 1 1 0 (0x06)

11.4 1 1 1 (0x07)

Table 5. LED Current Foldback Threshold

MAX16805/MAX16806

EEPROM-Programmable, High-Voltage, 350mA

LED Drivers with LED Current Foldback

______________________________________________________________________________________ 15

Thermal Foldback Knee Point (TFK)

The TFK register is a 4-bit register that sets the thermal

knee. Only the first 4 bits of the data byte program the

TFK register. The remaining 4 bits are ignored (see Table

6). The MAX16806 initiates dimming once the differential

voltage between TFP/SCL and TFN/SDA drops below the

programmed thermal foldback knee. The factory-default

MAX6613 thermal sensor output to +60°C.

Thermal Foldback Slope Gain Register

(0x04), MAX16806

Thermal Foldback Slope Gain register is a 2-bit register

that sets the gain after the thermal foldback knee. Only

the first 2 bits of the data byte program the Thermal

Foldback Slope Gain register. The remaining 6 bits are

ignored (see Table 7). The factory-default register value

is 4V/V.

THERMAL FOLDBACK

KNEE POINT (°C)

(MAX6613)

THERMAL FOLDBACK

KNEE POINT (mV)

BIT 3 BIT 2 BIT 1 BIT 0 HEX

60 1174 0 0 0 0 (0x00)

65 1118 0 0 0 1 (0x01)

70 1062 0 0 1 0 (0x02)

75 1006 0 0 1 1 (0x03)

80 950 0 1 0 0 (0x04)

85 894 0 1 0 1 (0x05)

90 838 0 1 1 0 (0x06)

96 782 0 1 1 1 (0x07)

101 726 1 0 0 0 (0x08)

106 670 1 0 0 1 (0x09)

111 615 1 0 1 0 (0x0A)

116 559 1 0 1 1 (0x0B)

121 503 1 1 0 0 (0x0C)

126 447 1 1 0 1 (0x0D)

131 391 1 1 1 0 (0x0E)

136 335 1 1 1 1 (0x0F)

Table 6. Thermal Foldback Knee

THERMAL FOLDBACK

SLOPE GAIN (V/V)

BIT 1 BIT 0 HEX

16 0 0 (0x00)

12 0 1 (0x01)

8 1 0 (0x02)

4 1 1 (0x03)

Table 7. Thermal Foldback Slope Gain

P1-P3 P4-P6 P7-P9 P10-P12 P13-P15 P16-P18 P19-P19

MAX16805ATP+T

Mfr. #:

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Manufacturer:

Maxim Integrated

Description:

LED Lighting Drivers EEPROM-Prog 350mA w/Current Foldback

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MAX16805ATP+T

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