LP8860-Q1: Problem with output power

Part Number:LP8860-Q1

Hi all,

i'm using lp8860 led driver in a design that have a nominal input Voltage of 13.5V.

Qhen the voltage is lowered up to 9.1V, the power consumption of the whole board begin to lower, because the led driver don't deliver all the necessary output power (I can see the Led backlight change luminosity).

Not all DUTS have this behaviour, in fact i have only two duts with this problem.

the values in eeprom registers are:

{ LP8860_EEPROM_REG_0, 0xef },
        { LP8860_EEPROM_REG_1, 0xff },
        { LP8860_EEPROM_REG_2, 0xdc },
        { LP8860_EEPROM_REG_3, 0xb1 },//60mA
        { LP8860_EEPROM_REG_4, 0x87 },
        { LP8860_EEPROM_REG_5, 0x05 },
        { LP8860_EEPROM_REG_6, 0xf2 },
        { LP8860_EEPROM_REG_7, 0x77 },
        { LP8860_EEPROM_REG_8, 0x77 },
        { LP8860_EEPROM_REG_9, 0x71 },
        { LP8860_EEPROM_REG_10, 0x3f },
        { LP8860_EEPROM_REG_11, 0xb7 },
        { LP8860_EEPROM_REG_12, 0x17 },
        { LP8860_EEPROM_REG_13, 0xef },
        { LP8860_EEPROM_REG_14, 0xb0 },
        { LP8860_EEPROM_REG_15, 0xE7 },
        { LP8860_EEPROM_REG_16, 0xEE },
        { LP8860_EEPROM_REG_17, 0x03 }, //BOOST FREQ TO 3 = 400KHz
        { LP8860_EEPROM_REG_18, 0xD9 },
        { LP8860_EEPROM_REG_19, 0x27 },
        { LP8860_EEPROM_REG_20, 0x30 },
        { LP8860_EEPROM_REG_21, 0xB7 },
        { LP8860_EEPROM_REG_22, 0xde },
        { LP8860_EEPROM_REG_23, 0x88 },
        { LP8860_EEPROM_REG_24, 0x3E },

any suggestion?

Thanks.

Alessio