Tzu Hao Chen

US Patent:

49947737, Feb 19, 1991

Filed:

Oct 13, 1988

Appl. No.:

7/257482

Inventors:

Tzu H. Chen - East Brunswick NJ
Mahesh Kumar - Lawrenceville NJ

International Classification:

H03H 1120

US Classification:

333164

Abstract:

A digitally controlled active phase shifter with vernier control consists of a 180 degree phase bit in series with a 90 degree bit and a digitally controlled active vector generator with vernier control. The digitally controlled active vector generator consists of an active power divider with digitally adjustable amplitude, a pair of phase delay networks with an active power combiner employing vernier control. The power divider consists of two sets of parallel pairs of FET's in cascode configuration with all input nodes connected together and all output nodes from the same set tied together. The FET at the output node of each pair is a common gate configuration with its gate RF grounded through a bypass capacitor. The gate bias voltage is applied to the common gate FET to switch it ON or OFF to thereby provide a set of desired signal amplitudes which can be obtained by selecting the gain of each of the cascode stages in each of the parallel pairs. Two output signals from the power divider are fed into a pair of phase delay networks to get 90 degree phase differences.

US Patent:

51500833, Sep 22, 1992

Filed:

Aug 9, 1990

Appl. No.:

7/565877

Inventors:

Tzu H. Chen - East Brunswick NJ
Mahesh Kumar - Lawrenceville NJ

Assignee:

Siemens Aktiengesellschaft - Berlin and Munich

International Classification:

H04Q 100

US Classification:

333103

Abstract:

There is described a 2. times. 2 switch matrix which includes four 1. times. 1 switch matrix modules. Each 1. times. 1 switch matrix module consists of an active power divider switch (APDS), an active power combiner switch (APCS) and an air bridge crossover. Additional APDSs and APCSs are utilized in the matrix to compensate for path length differences between different input to output signal paths thus providing good phase and amplitude tracking. The basic switch matrix modules are utilized to form a 2. times. 2 switch matrix whereby two primary input ports can be connected to any one of two primary output ports. The 2. times. 2 switch matrix is utilized to formulate larger matrix arrays as N. times. M configuration. Each of the active power divider switches and power combiner switches utilize two separate dual gate FETs which are suitably interconnected, depending upon whether the circuit is to be used as a power combiner or power divider.

US Patent:

20220387684, Dec 8, 2022

Filed:

May 28, 2021

Appl. No.:

17/334393

Inventors:

- Irvine CA, US
Tzu Tung Chen - Irvine CA, US
Clayton Poppe - Irvine CA, US

Assignee:

DIALITY INC. - Irvine CA

International Classification:

A61M 1/16
A61M 1/38
B01D 46/00

Abstract:

A portable hemodialysis system is provided including a dialyzer, a closed loop blood flow path which transports blood from a patient through the dialyzer and back to the patient, and a closed loop dialysate flow path which transports dialysate through the dialyzer. Preferably, the hemodialysis system includes a sorbent filter in the dialysate flow path. Furthermore, the hemodialysis machine includes a blood pump, and a pair of dialysate pumps. A processor controls the flow of blood through the blood flow path, and the processor controls the flow of dialysate through the dialysate flow path. In addition, the processor stores a patient treatment plan wherein the flow rate of the dialysate through the dialysate flow path reduces throughout the patient's treatment to maximize the amount of urea removed by the sorbent filter.

US Patent:

20220378992, Dec 1, 2022

Filed:

May 27, 2022

Appl. No.:

17/827506

Inventors:

- Irvine CA, US
Tzu Tung Chen - Irvine CA, US
Clayton Poppe - Irvine CA, US

International Classification:

A61M 1/16

Abstract:

A portable hemodialysis system is provided including a dialyzer, a closed loop blood flow path which transports blood from a patient through the dialyzer and back to the patient, and a closed loop dialysate flow path which transports dialysate through the dialyzer. Preferably, the hemodialysis system comprises a sorbent filter in the dialysate flow path. Furthermore, the hemodialysis system comprises a dialysate quality sensor disposed directly in the dialysate flow path. The dialysate quality sensor is configured to change color based on a pH level, ammonia level, or ammonium level of the dialysate.

US Patent:

20220378994, Dec 1, 2022

Filed:

May 26, 2022

Appl. No.:

17/825805

Inventors:

- Irvine CA, US
Tzu Tung Chen - Irvine CA, US

International Classification:

A61M 1/16
B01J 20/02
B01J 20/28

Abstract:

Sorbent regeneration systems for use in dialysis machines are described. Sorbent regeneration cartridges may include a layer of urease, a layer of acid zirconium phosphate, and a layer of sodium zirconium phosphate. An apparatus for conducting dialysis may include a sorbent cartridge, and a dialyzer in fluid communication with the sorbent cartridge, wherein spent dialysate passes from the dialyzer to and through the sorbent cartridge, and wherein the sorbent cartridge comprises a layer of urease, a layer of acid zirconium phosphate, and a layer of sodium zirconium phosphate. The urease may be immobilized to or associated with a carrier.

US Patent:

20220378995, Dec 1, 2022

Filed:

May 27, 2022

Appl. No.:

17/827578

Inventors:

- Irvine CA, US
Tzu Tung Chen - Irvine CA, US
Clayton Poppe - Irvine CA, US

International Classification:

A61M 1/16

Abstract:

A portable hemodialysis system is provided comprising a dialyzer, having a dialysate-replenishing system for replenishing minerals of dialysate in the dialyzer, the dialysate-replenishing system includes: a sorbent filter configured to remove ammonia from the dialysate, the sorbent filter having an outlet that outputs the dialysate to a dialysate flow path; a first reagent source containing a first reagent solution; a first pump configured to inject the first reagent solution into the dialysate flow path; a first mixer coupled to the dialysate flow path and downstream of the first pump, the first mixer configured to mix the dialysate with the first reagent solution; a conductivity sensor configured to measure a level of dissolved solids in the dialysate after the first mixer; and a controller configured to adjust a flow rate of the first reagent solution by adjusting the first pump based at least on the level of measured levels.