HT7991 Datasheet, PDF (1/13 Pages) Holtek Semiconductor Inc – Asynchronous Step-up PWM Converter

HT7991
2.5A Peak Current, 1MHz
Asynchronous Step-up PWM Converter
Features
• Input Voltage from 2.6V to 5.5V
• Adjustable Output Voltage Up to 12V
• Internal 0.2Ω Low Power Switch
• Fixed PWM Switching Frequency: 1MHz
• Precision Feedback Reference Voltage: 0.6V (±2%)
• Ultra Low Shutdown Current: 0.1μA
• Embedded Loop Frequency Compensation
• Programmable OCP Threshold via External
Resistor, ROC
• Complete Protections: Soft Start , UVLO, OCP,
OTP and OVP
• Package Type: SOT23-6
Applications
• All Single Cell Li or Dual Cell Battery Application
• Portable Equipment/Handheld Devices
General Description
The HT7991 is a current mode asynchronous step-
up DC-DC converter. The fully integrated power
MOSFET transistor, with its 0.2Ω drain source
resistance, ensures a high level of device power
efficiency. A fixed 1MHz switching frequency has
been chosen to permit smaller inductors to be used
in the application circuit. The error amplifier non-
inverting input amplifier is connected to an internal
precision 0.6V/±2% reference voltage while an
integrated soft-start function reduces the inrush
current during the converter start up period. The
device is available in a SOT23-6 package type.
Application Circuit
VIN=2.6V~4.2V
C1
47µF
C2
0.1µF
OFF
ON
R3
L1
3.3µH
HT7991
5
VIN
1
LX
4
EN
6
OC
3
FB
2
GND
D1
R1
R2
VOUT
C3
47µF
C4
0.1µF
Rev. 1.20
94.0%
V_OUT=5.1V
92.0%
90.0%
88.0%
86.0%
84.0%
Vin=3.3V
Vin=3.7V
Vin=4.2V
82.0%
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
I_OUT (A)
1
June 01, 2017