RT9750WSC datasheet(10/30 Pages) RICHTEK

10 / 30 page

RT9750

DS9750-01 June 2017

www.richtek.com

is a registered trademark of Richtek Technology Corporation.

Application Information

Device Power On

The internal bias circuit (VDDA) are powered from higher

of two voltages between VBUS and VOUT. The device will

powered on when the VDDA is higher than VDDA UVLO

threshold and EN pin is higher than VIH_EN. In VBUS >

VDDA UVLO & EN pin from low logic to high logic

condition, the device need maximum 500

μs turn on delay

time after EN pin set to high logic.

Smart Load Switch

The RT9750 is a 8m

Ω RON and loading can up to 6-A

smart load switch battery charger. The load switch can

be controlled by the host via I2C. The load switch can be

turn on by set CHG_EN bit to “1” (0x06 bit4) if no

protection event happened (Please check 0X03 & 0X04).

The load switch can be turn off by set CHG_EN bit to “0”

or pull EN pin to low. If the protection event happen the

load switch will be turn off automatically and set CHG_EN

bit to “0” The smart load switch also implement soft-on

& soft off to function minimize the inrush current and

voltage spike.

8-Channel 12-bit Analog to Digital Converter

The device integrate 8-Cannel 12 bit ADC function, user

can monitor voltage of VBUS, VOUT, VDROP (voltage

different between VBUS and VOUT), and VBAT. The user

also can monitor the internal junction temperature, battery

temperature (by external resistor divider and NTC

thermistor), and VBUS temperature (by external resistor

divider and NTC thermistor). The ADC function also provide

IBUS information for user to monitor.

User can set ADC_EN (0x07 bit3) bit to enable or disable

ADC conversion. User also can enable or disable ADC

channels respective by using register 0x07 and 0x08. The

ADC has two conversion rate 1- shot mode and continuous

mode. User can select the mode by ADC_RATE bit (0X07

bit2).

1. 1-shot mode

In this mode, user need to set ADC_EN bit to 1 to start

ADC conversion. The ADC_EN bit will change to 0

automatically after ADC start conversion. After the ADC

conversion complete, the ADC_DONE bit (0x04 bit6) will

change to 1 and INT pin will pull low if the

ADC_DONE_MASK bit is no mask. The typical conversion

time of one channel is 100

μs (16 averages).

2. Continuous mode

In continuous mode, ADC conversion continuously if user

set ADC_EN bit to 1 and ADC stop conversion if user set

ADC_EN bit to 0.

User can set the ADC_AVG_EN bit to enable or disable

ADC measurement averaging function in both 1-shot mode

and continuous mode. If ADC_AVG_EN = 0 the ADC is

instantaneous measurement. IfADC_AVG_EN= 1 the ADC

is averaging measurement and user can set the number

of samples by ADC_SAMPLES bit.

Linear Regulation Mode (LDO)

The load switch implement LDO mode to regulate VOUT

voltage, battery voltage and input current. If an event that

VOUT_REG, VBAT_REG or IBUS_REG threshold is

exceeded, the load switch act as LDO and will regulate

VOUT, VBAT, IBUS (depending upon which threshold is

exceeded). These regulations threshold can be selected

by I2C.

Protection Features

The load switch implement 5 way hardware protection

and 2 temperature protection as below. All these protection

functions have IRQ and active with INT pin to inform host

to monitor which protection is active.

1. VBUS Over-Voltage Protection (VBUS_OVP)

When VBUS_OVP event is happened the device will turn

off load switch and the CHG_EN bit will be set to 0. User

can enable or disable this protection function by I2C 0x06

bit 7. The protection threshold and deglitch time also can

be selected by I2C (Protection threshold is 0x0A, deglitch

time is 0x09 bit0).

2. VBUS Over-Temperature Protection (TSVBUS_OTP)

As below picture, user need to place an external NTC

voltage dived circuit at TSBUS pin. When the voltage of

TSBUS pin is over the threshold, the device will turn off

load switch and set CHG_EN bit to 0. User can enable or

RT9750WSC Datasheet(PDF) 10 Page - Richtek Technology Corporation

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