RT9758 datasheet(43/61 Pages) RICHTEK

43 / 61 page

RT9758

is a registered trademark of Richtek Technology Corporation.

DS9758-03

May 2023

www.richtek.com

⚫

Input and Output Over-Voltage Protection (VBUS_OVP, VOUT_OVP)

The device integrates VBUS_OVP and VOUT_OVP function to monitor input and output voltage by VBUS pin and

VOUT pin, respectively. When the device in standby mode or 4 operation modes, if the VBUS voltage is higher

than VBUS_OVP threshold or the VOUT voltage is higher than VOUT_OVP threshold, the device will start to turn

off charger in tVBUS_OVP_RE time or tVOUT_OVP_DEG time, respectively.

There are two register bits related to OVP protection which are AUTO_RECOVERY_EN and

IN_VALID_RECOVERY_DEGLITCH. According to different two of register setting, the device shows different

protection method in bypass mode. For example, in bypass mode with default setting (AUTO_RECOVERY_EN =

1 and IN_VALID_RECOVERY_DEGLITCH = 0), the device stop charge while OVP is triggered. And if OVP fault

is released, the device will count 21msec deglitch time (tOVP_RECOVERY) to make sure OVP fault is released

actually. After deglitch counting is finished, the device can re-start again. In other three operation modes,

regardless of two of bit setting, the device will set CHG_EN = 0 when OVP is triggered. About OVP protection

behavior, the Table 7 shows relational behavior in each mode. Users can adjust the threshold of VBUS_OVP and

VOUT_OVP via register setting. For safety charging, the OVP level must be set to 1.1 times the level of operating

voltage. And make sure the input and output voltage not be higher than absolute maximum rating of VBUS,

WRX_IN and VOUT pin. (prevented by external TVS or OVP IC, etc.).

Table 7. OVP Protection Behavior in Each Mode

Bypass Mode

AUTO_RECOVERY_EN

IN_VALID_RECOVERY_DEGLITCH

OVP Protection Behavior

Reset CHG_EN = 0

Stop charge until fault release

over 21msec deglitch time

Stop charge until fault release

over 100msec deglitch time

Reverse Bypass Mode, DIV2 Mode and Reverse DIV2 Mode

Reset CHG_EN = 0

⚫

VBUS Charge Voltage Protection (VBUS_LOW_ERR)

The device integrates VBUS_LOW_ERR to prevent users from adjusting wrong VBUS for charge. In standby

mode, if VBUS is lower than VBUS_LOW_ERR falling threshold, the VBUS_LOW_ERR flag and status bit will set

to 1. If VBUS is higher than VBUS_LOW_ERR rising threshold, the VBUS _LOW_ERR status bit will set to 0. The

VBUS_LOW_ERR threshold is depending on OPERATION_MODE_SELECTION bit, if OPERATION_MODE_

SELECTION set to 0, the VBUS_LOW_ERR typical falling threshold is 0.99V/V. If OPERATION_

MODE_SELECTION set to 1, the VBUS_LOW_ERR typical threshold is 1.975V/V. Before start charging in 4

operation modes, user should follow the rule of VBUS_LOW_ERR shown in Table 8. If VBUS_LOW_ERR condition

isn’t meet the rule, the device will not enter charging process. In above case, the device will keep to like standby

mode until the VBUS_LOW_ERR condition is met. For recommended setup process before start charging, set the

device

into

standby

mode

(CHG_EN

and

then

make

sure

VBUS_LOW_ERR

status,

OPERATION_MODE_SELECTION bit and REVERSE_MODE_EN bit are ready. After the device start charging,

the VBUS_LOW_ERR function will be disabled.

RT9758 数据表(PDF) 43 Page - Richtek Technology Corporation

RT9758 数据表(HTML) 43 Page - Richtek Technology Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61

数据表下载