Document
GR8876A
Green-Mode PWM Controller with Integrated Protections
Features
High-voltage (500V) startup circuit Current mode PWM Very low startup current (<20uA) Under-voltage lockout (UVLO) Non-audible-noise green-mode control Programmable switching frequency Cycle-by-cycle peak current limiting Internal leading-edge blanking Internal slope compensation Internal 4ms soft start (Fs = 65KHz) Gate output voltage clamp Soft driving for reducing EMI Over-voltage protection (OVP) on Vcc pin Over-load protection (OLP) 500mA driving capability
Applications
Open-frame SMPS
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Switching AC/DC adapter
Description
The GR8876A is a highly-integrated, low startup current, current mode PWM controller with
green-mode function and high-voltage start up circuit. A high-voltage current source supplies the start up current and the traditional start-up resistor can be saved in order to reduce the power dissipation due to start-up resistor. The controller also includes the leading-edge blanking of the current sensing, internal slope compensation and cycle-by-cycle peak current limiting. It is also integrated soft driving for reducing EMI, gate output voltage clamp function for protecting power
MOSFET. GR8876A provides several protections such as OLP, OVP, and OCP for fault conditions. The GR8876A improves the performance and reduces the cost of power supplies. It is available in both 8-pin SOP,7-pin SOP and 8-pin DIP package.
Ordering and Marking Information
DIP-8/SOP-8/SOP-7
Code 1 8 9 A B Year 2008 2009 2010 2011 Code 2 1 2 3 4 Month Jan. Feb. Mar. Apr.
● ● ●
G 2016 9 Sep.
H 2017 A Oct.
I J 2018 2019 B C Nov. Dec.
Grenergy OPTO Inc. reserves the right to make changes to improve reliability or manufacture ability without notice, and advise customers to obtain the latest version of relevant information to verify before placing orders.
2010.10 Ver. 1.0 Copyright Grenergy OPTO, Inc. www.grenergy-ic.com
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GR8876A
Pin Configuration
SOP-8 / DIP-8 TOP VIEW SOP-7 TOP VIEW
Pin Description
Pin 1 2 3 4 5 6 7 8 Symbol RT COMP CS GND OUT VCC NC HV Description Connecting a resistor to ground, this resistor determine the switching frequency Voltage feedback pin, by connecting a photo-coupler to control the duty cycle Current sense pin, connect to sense the MOSFET current Ground The output for driving the external MOSFET Power supply pin Unconnected pin This pin is connected to positive terminal of bulk capacitor. It provides the startup current. When UVLO (on) is tripped, this HV loop will be off thus limit the power loss on the startup circuit.
Absolute Maximum Ratings
Supply voltage VCC High-voltage pin, HV COMP, RT, CS -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------35V -0.3 ~ 500V -0.3 ~ 7V 150
Junction temperature
℃ Operating ambient temperature ----------------------------------------------------------------------.