RT5707/A
V
IN
V
OUT
V
IN
V
TH_100+
V
TH_100-
V
OUT_target
V
O
tracks V
IN
100% duty cycle
100% duty cycle
Over-Current Protection
The OCP function is implemented by UGATE and LGATE.
When the inductor current reaches the UGATE current
limit threshold, the high-side MOSFET will be turned-off.
The low-side MOSFET turns on to discharge the inductor
V
OUT
Step Down Operation
current until the inductor current trips below the LGATE
V
O
tracks V
IN
V
UVLO+
V
UVLO-
current limit threshold. After UGATE current limit triggered,
the max inductor current is decided by the inductor current
rising rate and the response delay time of the internal
network.
Soft-start
During OCP period, the output voltage drops below the
setting threshold (typ. 0.4V) and the current limit value is
reduced for lowering the devices loss, reducing the heat
and preventing further damage of the chip.
Output Voltage Selection
The RT5707/A provides 8 level output voltages which can
be programmed via the volatage select pin VSEL1 to
VSEL3. Table 1 indicates the setting to indivdual output
voltage.
Figure 1. Automatic Transition into 100% Duty Cycle
Over-Temperature Protection
When the junction temperature exceeds the OTP
threshold value, the IC will shut down the switching
operation. Once the junction temperature cools down and
is lower than the OTP lower threshold, the converter will
automatically resume switching.
Table 1. Output Voltage Setting
Device
V
OUT
(V)
1.2
1.5
1.8
2.1
2.5
2.8
3
3.3
0.7
1
1.3
1.6
1.9
2
2.9
3.1
VSEL3
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
VSEL2
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
VSEL1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
RT5707
RT5707A
Copyright
©
2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS5707/A-03 February 2019
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
