View cs3524a.rev2 datasheet:

CS3524A Voltage Mode PWM Control Circuit with 200mA Output Drivers Description Features The CS3524A PWM control circuit The CS3524A features an undervoltage Precision Reference lockout circuit which disables all inter- retains the same versatile architecture Internally Trimmed to ±1% nal circuitry (except the reference) until of the industry standard CS3524 Current Limit the input voltage has risen to 8V. This (SG3524) while adding substantial holds standby current low until turn- Undervoltage Lockout improvements. on, and greatly simplifies the design of Start-up Supply Current The CS3524 is pin-compatible with low power, off-line supplies. The turn- < 4mA “non-A” versions, and in most applica- on circuit has approximately 600mV of tions can be directly intercha