LTC7841 no-OS driver

Supported Devices

Overview

The LTC7841 is a high performance PolyPhase single output synchronous boost converter controller that drives two N-channel power MOSFET stages out-of-phase. Multiphase operation reduces input and output capacitor requirements and allows the use of smaller inductors than the single-phase equivalent. Synchronous rectification increases efficiency, reduces power loss and eases thermal requirements, enabling high power boost applications. The output voltage can be adjusted up to 60V with 0.2% resolution via a PMBUS-compliant serial interface. The serial interface can also be used to read back fault status, input/output current, input/output voltage and temperature.

Applications

LTC7841

Automotive Systems, Medical, Industrial

LTC7841 Device Configuration

Driver Initialization

In order to be able to use the device, you will have to provide the support for the communication protocol (I2C).

The first API to be called is ltc7841_init. Make sure that it returns 0, which means that the driver was initialized correctly.

Status Bytes

Assertion in the status bytes/words indicates fault/warning in device input/ output, temperature, and communication, memory and logic. These statuses can be accessed via the ltc7841_read_status API.

Telemetry

Measurements for each output channel can be read using the ltc7841_read_value API. Some telemetry values includes input/output voltage, input/output current and die temperature.

VOUT Configuration

The LTC7841 output voltage is programmable from 0V to 48V. These can be configured using the ltc7841_vout_value API.

LTC7841 Driver Initialization Example

struct ltc7841_desc *ltp8800_desc;

struct ltc7841_init_param ltc7841_ip = {
        .comm_param = {
        .device_id      = LTC7841_I2C_DEVICE_ID,
        .max_speed_hz   = LTC7841_I2C_CLK_SPEED,
        .slave_address  = LTC7841_I2C_ADDR,
        .platform_ops   = &max_i2c_ops,
        .extra          = (void *)&ltc7841_i2c_extra,
    },
    .regs = ltc7841_regs
};

ret = ltc7841_init(&ltp8800_desc, &ltc7841_ip);
if (ret)
{
        goto error;
}

LTC7841 no-OS IIO support

The LTC7841 IIO driver comes on top of the LTC7841 driver and offers support for interfacing IIO clients through libiio.

LTC7841 IIO Device Configuration

Channels

The device has a total of 3 input channels and 2 output channels. The input consists of the input voltage, input current, and the forward diode temperature. The output consists of the output voltage and current.

vout - output voltage
iout - output current
vin - input voltage
iin - input current
temperature - forward diode temperature

Channel Attributes

Each channels has 1 channel attribute:

raw - the raw value of the channel

Global Attributes

The device has a total of 1 global attribute:

vout_command - VOUT_COMMAND value of the channel output

Debug Attributes

The device has a total of 1 debug attribute:

status_word - Status word value

LTC7841 IIO Driver Initialization Example

    int ret;

    struct ltc7841_iio_desc *ltc7841_iio_desc;
    struct ltc7841_iio_desc_init_param ltc7841_iio_ip =
{
            .ltc7841_init_param = &ltc7841_ip,
    };

    struct iio_app_desc *app;
    struct iio_app_init_param app_init_param = { 0 };

    ret = ltc7841_iio_init(&ltc7841_iio_desc, &ltc7841_iio_ip);
    if (ret)
{
            goto exit;
}

    struct iio_app_device iio_devices[] =
{
            {
                    .name = "ltc7841",
                    .dev = ltc7841_iio_desc,
                    .dev_descriptor = ltc7841_iio_desc->iio_dev,
            }
    };

    app_init_param.devices = iio_devices;
    app_init_param.nb_devices = NO_OS_ARRAY_SIZE(iio_devices);
    app_init_param.uart_init_params = uart_ip;

    ret = iio_app_init(&app, app_init_param);
    if (ret)
    {
            return ret;
    }

    return iio_app_run(app);