STAR4000

Description

STAR4000 consists of a frequency regulated voltage doubler (to produce VQQ) followed by a frequency-regulated voltage tripler (to produce VPP). The regulation loop on VPP and VQQ allows the user to program the output voltage levels of the charge pump by setting configuration bits. The charge pump output voltage levels are frequency regulated, which means that the charge pump output voltage is directly proportional to the frequency of the VCO, which generates the charge pump clocks. The VCO is a current starved ring oscillator, whose frequency can be controlled from 0-120MHz. The amount of current starving (hence speed) of the VCO, is controlled by comparing the output voltage (VPP or VQQ) to a programmable reference voltage.

The charge pump architecture itself is implemented using a switch-bootstrapped, Cockcroft-Walton architecture. Switch-bootstrapping allows improves the drive capability and increases efficiency by preventing short-circuit losses. The Cockcroft-Walton architecture allows the use of standard CMOS logic devices, without the need to resorting to a high-voltage process. This allows the user to save on the cost of adding an extra (often expensive) mask layer. In order to prevent over-voltage issues with the charge-pump, integrated over-voltage protection structures are added to ensure reliable operation at high voltage levels.

Features

• OTP memory charge pump

• 4 bit at-a-time programming capability

• Input voltage: 1.8V/1.1V supply

• Two charge pump outputs (VPP and VQQ)

• Implemented using standard CMOS devices (no high voltage devices, or special mask layers)

• VQQ programmable output range: 2.35V – 3.1V

• VPP programmable output range: 4.85V – 5.64V

• Independent control of the VPP and VQQ charge-pumps

• VPP current-carrying capability: 1.6mA

• Low drive mode for low power mode

• Internal over-voltage protection

• Power Efficiency: 25.6%

• Current Efficiency: 9.0%

• Power consumption: 33.5mW

• TSMC 40nm-G process

Applications

• OTP memory programming power source

• High voltage power supply

• Low power systems

• Energy harvesting