Description of the functional blocks for the cross-coupled charge pump design algorithm

Abstract

This paper presents the circuit model that is used for the cross-coupled charge pump design algorithm. Symbolic description of the pump stage model as an analog functional block for high-voltage application is firstly discussed. Design process has been done by using simplified BSIM model equations assuming the long channel MOSFET. Characteristics have been verified by ELDO Spice and compared with the found relationships. Static and dynamic parameters of the subcircuit have been tested in two-stages structure by LT Spice simulator. Analysis results show the consistency between model and real circuits characteristics under given conditions. Complex model provides the reliable results for significantly smaller strange capacitances in comparision with the main pump capacitances. The model can be used for design and prediction of the pump parameters without long-time simulation process. The strong inversion region of MOSFET is expected, thus equations are correct for other MOSFET models that are used in chip design (PSP).

A Program Procedure for Estimation of the Cross-Coupled Charge Pump Properties

“…1) through the mathematical description is a comprehensive task. Many reasons have been mentioned and demonstrated by the simulation results [5]. Simulations are the usual way of the optimal quasi-analog circuits design.…”

“…Digital model is not an option due to its low accuracy. However, another aproach has already been outlined in [5]. The previous research has been focused on the description of circuit behavior as an analog block.…”

“…Complete model of each of the stages and last stage (Fig. 2) is detailed in [5]. Behavior of the model was tested in N-stages charge pump by the simulator LT SPICE.…”

“…2. Subcircuit of the i-pump stage (a) and the last stage (b) [5] built on the mentioned work. In this paper, the attention will be focused on the program procedure, which allow to estimate the charge pump properties.…”

Complex model description and main capacitor sizing for the cross-coupled charge pump synthesis process

“…Easy integrability is among the main advantages of DC/DC converters without inductors. Modern architecture of the cross-coupled charge pump [1] with driving feedback circuit was presented in detail from theoretical analysis [2,3] through the simulations of real properties [4,5] to the mathematical model [6,7], which is including important properties of the circuit structure. The pump stage has been described as an analog subcircuit, labeled X n and X L see Fig.…”