iW1700-00

iW1700 Zero Power No-Load Off-Line Digital PWM Controller 1 Description The iW1700 is a high performance AC/DC power supply controller which uses digital control technology to build peak current mode PWM flyback power supplies. The device together with an external active device (depletion mode NFET or NPN BJT) provides a fast start-up meanwhile achieving ultra-low no-load power consumption. The device directly drives a power BJT and operates in quasi-resonant mode to provide high efficiency along with a number of key built-in protection features while minimizing the external component count, simplifying EMI design and lowering the total bill of material cost. The iW1700 removes the need for secondary feedback circuitry while achieving excellent line and load regulation. It also eliminates the need for loop compensation components while maintaining stability over all operating conditions. Pulse-by-pulse waveform analysis allows for a loop response that is much faster than traditional solutions, resulting in improved dynamic load response, for both one-time and repetitive load transient. The built-in power limit function enables optimized transformer design in universal off-line applications and allows for a wide input voltage range. Dialogs innovative proprietary technology ensures that power supplies built with the iW1700 can achieve both highest average efficiency and zero no-load power consumption, and have fast load transient response in a compact form factor. The active start-up scheme enables shortest possible start-up time without sacrificing no-load power loss. 2 Features Active start-up scheme enables fastest possible start-up Zero power consumption at no-load with lowest system cost (< 5 mW at 230 V with typical AC Adaptive multi-mode PWM/PFM control improves application circuit) efficiency Intelligent low power management achieves ultra-low Quasi-resonant operation for highest overall efficiency operating current at no-load Direct drive of low-cost BJT switch Adaptive load transient detection and fast response No external compensation components required Very tight constant voltage and constant current Complies with EPA 2.0 energy-efficiency specifications regulation over entire operating range with ample margin TM PrimAccurate primary-side feedback eliminates Built-in soft start optocouplers and simplifies design TM Built-in short circuit protection and output overvoltage EZ-EMI design enhances manufacturability protection Intrinsically low common mode noise Built-in current sense resistor short circuit protection Optimized 72kHz maximum PWM switching No audible noise over entire operating range frequency achieves best size and efficiency 3 Applications Compact AC/DC adapter/chargers for cell phones, PDAs, digital still cameras Linear AC/DC replacement 01-Apr-2020 Datasheet Rev. 1.7 www.dialog-semiconductor.com 1 of 16 2020 Dialog SemiconductoriW1700 Zero Power No-Load Off-Line Digital PWM Controller L V OUT + + GND N U1 iW1700 1 V OUTPUT 6 CC 2 V GND 5 SENSE 3 4 ASU I SENSE Figure 3.1: iW1700 Typical Application Circuit (Achieving < 5 mW No-load Power Consumption. Using Depletion Mode NFET as Active Start-up Device) L V OUT + + GND N U1 iW1700 1 6 V OUTPUT CC 5 2 V GND SENSE 3 4 ASU I SENSE Figure 3.2: iW1700 Typical Application Circuit (Alternative Circuit Using NPN BJT as the Active Start-up Device) 01-Apr-2020 Datasheet Rev. 1.7 www.dialog-semiconductor.com 2 of 16 2020 Dialog Semiconductor