In this paper, we proposed an improved true random number generator (TRNG), which comprises a low-bias hardware random number generator (HRNG) and a scrambler based on linear-feedback shift register (LFSR). The HRNG reduces both DC offset from the noise sources and offset voltage from the comparator to generate low-bias bitstream. The LFSR-based scrambler further reduces the bias to zero without sacrificing the throughput rate. Randomness quality is verified by Monte Carlo simulations using the randomness test suite.