HIGH PRECISION CC/CV PRIMARY SIDE SWITCH 
  
  
DESCRIPTION  
  
The UTC USRB01A is a primary controller for charger and  
adapter applications. The controlled variable is transferred by an  
auxiliary winding from the secondary to the primary side. The  
device uses Pulse Frequency Modulation (PFM) method to build  
discontinuous conduction mode (DCM) flyback power supplies.    
The UTC USRB01A operates in primary-side sensing and  
regulation. Opto-coupler and TL431 could be eliminated. It also  
eliminates the need of loop compensation circuitry while 
maintaining stability.    
The UTC USRB01A achieves high precision CV/CC  
regulation and high power efficiency. It offers comprehensive  
protection coverage with auto-recovery features including  
Cycle-by-cycle current limiting, output over voltage protection,  
VDD over voltage protection, feedback loop open protection, short  
circuit protection, leading edge blanking, OTP, VDD under voltage  
lockout, etc.  
  
FEATURES  
  
* ±5% constant voltage regulation at universal AC input  
* Primary side control without TL431 and opto-coupler  
* High precision constant current regulation at universal AC input  
* Programmable CV and CC regulation  
* Eliminates control loop compensation circuitry  
* Flyback topology in DCM operation  
* Random frequency modulation to reduce system EMI  
* Built-in power NPN  
* Programmable cable drop compensation  
* Built-in leading edge blanking  
* Built-in primary winding inductance compensation  
* Open circuit protection  
* Output over voltage protection  
* VDD over voltage protection  
* Short circuit protection  
* Over temperature protection  |